“You promised, Stiles.” Derek’s voice brooked no argument. “That’s the deal. If you’re gonna make me put my dick in this scary goop, you’re going to entertain me in whichever way I choose while I try and stay hard for you.”
“But I thought you were joking about the panties.” Stiles protested. Derek caught his scent, suddenly stronger in the space between them as a flush spread over his face and down his throat. He held Derek’s gaze.
“Pervert,” Stiles said. But a slow, dirty smile curved his lips, and Derek knew he’d won. “You get naked then, while I get... well, nearly naked. Oh, and put some water on to heat up too. We need warm water for the kit.”
They’d already read the instructions carefully and worked out what they needed to do. They were in the kitchen of Stiles’ house with the blinds down for added privacy, they definitely didn’t want to get spotted doing this by the mailman or any random visitors. The sheriff wasn’t due back for hours and they had everything laid out ready on the table.
Derek stripped his clothes off quickly, loving the way that Stiles’ gaze raked over his skin as it was exposed. Derek watched Stiles in turn, admiring the grace and flex of his torso as he pulled his T-shirt over his head, eyes snagging on the dark line of hair on his belly that led down into his jeans. Stiles caught his gaze and grinned, then deliberately turned and he unfastened his jeans and shimmied out of them, pushing his underwear down at the same time, exposing his perfect ass to Derek’s hungry gaze.
It had been amazing watching Stiles grow in confidence, sexually. In the few months that they’d been dating, Stiles had transformed from awkward, unsure teenager into this sexy, provocative man. He was all too aware of the power he had over Derek and he reveled in it. Derek wasn’t complaining either.
Derek stepped up close behind Stiles, running his hands over the firm flesh. His cock poked Stiles, trying to get in on the action. Clearly getting hard wasn’t going to be a problem, even if staying hard might be. “I’m gonna miss that ass,” he murmured.
Stiles pushed back into his hands and wiggled as he straightened up, leaning back and exposing his throat to Derek. “Maybe we should buy an ass casting kit too, then you can have that to remember me by while I’m away in college. It’s only fair, if I get to take a hard copy of your dick away with me.” His voice was light and full of humor, but Derek caught the sharp tang of regret in his scent as he licked and nuzzled at the taut column of Stiles’ neck. Being apart was going to be painful for both of them.
“Well let’s just see how this works out today,” Derek replied. “One body part at a time, okay?”
Stiles chuckled. “Yeah.” Then he turned in Derek’s arms and curled his fingers around Derek’s cock, gripping it firmly. “Come on then big boy. Let’s do this thing.”
Stiles’ breath was warm as it washed across Derek’s lips, and Derek leaned in and kissed him, sucking on his lower lip and releasing it with a pop. “Get the panties on first.”
Stiles rolled his eyes as he pulled away. “You’re so demanding. Keep yourself hard while I get them on, we need you at full mast so we can cut the tube to size.”
“Won’t be a problem.” Derek grinned. But he took his erection in hand and stroked it anyway, because he was horny and it felt good. He couldn’t wait to get this stupid penis casting over with, so he could bury his dick in Stiles’ ass where it belonged instead of in a plastic tube full of lukewarm goop.
Derek sat back in one of the kitchen chairs, the wood cool against his bare skin. He watched as Stiles got a scrap of dark blue fabric out of a bag and bent, stepping into the barely-there panties and sliding them up his legs. He had his back to Derek again, and once he had them in place around his slim hips he turned his head and looked over his shoulder.
Derek cleared his throat, hand working his cock slowly as he replied. “Uh... yeah. That ought to do it.”
He definitely wasn’t going to have any trouble keeping it up with Stiles wearing those, goop or no goop. The fabric clung to Stiles’ ass, bisecting each buttock so that the lush curve of bare skin was exposed beneath the stretchy blue material.
“Turn around.” Derek’s voice was embarrassingly strained. The smile that lurked at the corners of Stiles’ mouth showed that he was enjoying this. It had taken him weeks to completely believe how attracted Derek was to him, but Derek had enjoyed proving it in a variety of different and creative ways until all of Stiles’ doubts had been swept away.
Stiles turned obediently, adjusting his cock as he did, and Derek was glad to see that he was hard too. Stiles’ dick was barely contained by the skimpy front panel and his balls were escaping out of the side along with a dark fuzz of pubic hair. He should have looked ridiculous, but Derek’s libido didn’t care about the details. The need to see Stiles in panties was a thing that he couldn’t explain, but as soon as the thought had occurred to Derek he’d needed it. And this little foray into penis casting had given him the perfect excuse to ask for it.
“They don’t really fit.” Stiles tried and failed to tuck his balls back into the lace panel.
“I’d be worried if they did.” Derek grinned. His gaze swept up to Stiles’ face to take in the hectic flush on his cheeks, before dragging back down over his torso to the obscene bulge in the panties. “Come here.” He stroked his cock harder, feeling the pulse of it against his palm as he squeezed.
“Nope.” Stiles shook his head and turned to pick up a clear plastic tube and a sharpie. “You’ll just distract me. We’re doing this first. Then we get to play.” He approached Derek. “Are you fully hard?”
Derek took his hand away from his dick, letting it spring up against his belly with a satisfying thwack and spreading his legs invitingly. “Wanna check?”
Stiles’ pupils flared and the scent of sex was so strong now that Derek could almost taste Stiles’ musk in the air. Derek licked his lips and swallowed hard as Stiles eyed his cock consideringly. “Hmm.” He kneeled and looked up at Derek from under his lashes. His breath ghosted over the hot skin and Derek’s cock jerked eagerly. “Let me just...”
Stiles opened his mouth and sucked Derek in, drawing his foreskin back with his lips and swirling his tongue around the head. He pulled off and used his hand to stroke Derek a couple more times. “That’s better. I want the head fully exposed for the cast. It’ll make a better dildo with the rim uncovered. And you look beautiful like this, your cock is a work of art.”
Derek snorted. “If you say so.”
Stiles used just the light touch of his fingers at the base to guide Derek’s erection into the tube, and marked where it came to with a sharpie. “Now, keep yourself hard while I cut this and get the warm water ready.”
Derek jerked himself slowly. There was no danger of him not staying hard. The sight of Stiles’ ass in those panties as he turned away to cut the tube and pour and mix water to the right temperature, was more than enough to keep Derek’s cock interested.
“Okay.” Stiles turned with a jug of water in one hand and a bowl in the other. “The water’s the right temperature. Are you good to go if I mix this stuff up now.”
“I think I might have softened a bit, with all the waiting around. You should blow me again, just to make sure.” Stiles had promised to keep him hard, so Derek was going to make the most of it.
Stiles’ eyes narrowed but he lowered himself obediently, kneeling at Derek’s feet as he took Derek back into the wet heat of his mouth and sucked him a few times before pulling off to glare at Derek. “You’re such a liar.”
Derek grinned. “I like to think of myself as an opportunist.”
“Okay.” Stiles got to his feet again. “Are you ready? We need to be really fast once I’ve mixed it, and then when your dick’s in the tube I’ll entertain you while you think dirty thoughts about me.”
“Works for me.”
Derek sat back and watched, stroking himself idly as Stiles moved quickly, pouring and stirring. He looked like he was doing a science experiment and his focus and complete unselfconsciousness--despite the panties that were stretched tight over his erection--was insanely hot. Derek let go of his dick abruptly, suddenly realizing that he was in danger of coming already.
“Quick!” Stiles turned with the tube full of lumpy white gunk that looked a little like runny oatmeal. “I’ve set the timer. We have five minutes before it sets completely.”
“That looks gross.” Derek wrinkled his nose. “How are we doing this?”
“Stand up and lean forward, guide yourself in.” Stiles held the tube out as Derek followed the instructions. Once the tube was flush against his groin, Derek straightened up, and then winced as the displaced mixture dribbled down his legs, sticking to the hairs.
“Eww. That feels totally bizarre.” At least the mixture was warm, but the whole process was taking its toll on Derek’s boner. He sat back in the chair, holding the tube carefully in position. “Come on, we’ve got to keep me hard for a few minutes now. Show me what you’ve got.”
Stiles flushed, but he didn’t waste any time. He ran his hands teasingly down over his abs and rubbed at his cock through the silky fabric. “I’m making a mess of these.” He traced the head with a fingertip, showing Derek a damp patch that was seeping through and turning the blue even darker.
Derek’s nostrils flared, seeking and finding the salt-sweet scent of him. “Show me.” His voice was a deep rumble and he felt the pulse in his cock as it swelled a little more in the thickening mixture.
Stiles pushed the panties down below his balls and his cock reared up, the pink flush of the head matching Stiles’ cheeks as he took himself in hand and fucked into his fist. A little involuntary whimper escaped as he jerked himself. “Oh fuck,” he gasped. “Feels good. But I wish you were in me. Will you fuck me later? when we’re done with this?”
“Yes.” Derek hissed through clenched teeth, his cock a sweet, hot throb in the ever-tightening grip of the mold.
“I want to bend over the kitchen table while you open me up with your tongue and your fingers.” Stiles’ hand was moving faster now, his breath ragged as he huffed out the words.
“Do it.” Derek demanded. “I can do that for you now.”
“Fuck.” Stiles turned, sweeping scissors and bits of tube and other assorted crap off the kitchen table in a noisy clatter. He bent over, pushing the panties down around his thighs and pulled his cheeks apart, fingers questing into his crack. Derek moved to kneel behind him, one hand supporting the tube that was still around his cock, the other batting Stiles’ fingers aside so he could replace them with his tongue.
Stiles made a strangled sound as Derek swiped over his hole with a long, slow lick and the muscle clenched under Derek’s tongue. He pressed against it, licking harder and used a finger too, easing it into Stiles as he moaned and pushed back.
The shrill buzz of the timer made them both jump. But Derek ignored it, fucking into Stiles with finger and tongue, crazed with the need to be inside him.
“Derek.” Stiles sounded wrecked, barely managing to get the words out. “The mold...”
“Fuck the mold.”
Derek’s voice was muffled by Stiles’ ass, but he was hoping his tone would make it abundantly clear that the mold could fucking well wait, because Derek was busy. He was actually grateful for the warm pressure of it around his dick. It wasn’t even close to as hot and perfect as Stiles’ ass, and it lacked friction as his hips bucked instinctively into it. But it felt good, gripping Derek like a smooth fist, easing the ache of his arousal just enough. He worked another finger into Stiles, curling them just right and rubbing so that Stiles groaned and clenched around him. He had one hand beneath himself, stroking himself furiously as Derek’s fingers moved, bringing him to the brink.
“Oh-my-God-Derek... I’m gonna... fuck. This is my dad’s kitchen table. This is so wrong...”
But it obviously wasn’t wrong enough to stop Stiles as his words tailed off into a long, drawn-out moan and he pulsed, hot and tight around Derek’s fingers. The thick scent of his come filled Derek’s senses and sent him spiraling into orgasm. The pleasure was so intense, so shocking and it just kept on and on. The pressure built in Derek’s cock until it verged on pain, then suddenly there was a sharp cracking sound.
“Oh... fuck.” Derek felt sharp edges of broken plastic under his palm where he was still holding the tube, and as the intense waves of release continued to roll through Derek again and again he realized he’d knotted the mold and had split the tube with the swelling at the base of his shaft.
Stiles had collapsed over the kitchen table, panting as though he’d run a marathon. “What the fuck was that? Are you okay?”
Finally spent, Derek looked down at the destruction that his dick had wrought. “Um. Yeah, I’m fine. But I broke the mold.”
“Huh?” Stiles pushed himself up and turned to see. “Fuck, Derek. What happened? Oh my god. You knotted the fucking mold? How is that even possible? You’ve never even done that to my ass!”
“I... uh... I may have gotten a little carried away.” Derek admitted, blushing hard. “I don’t know, okay? It doesn’t usually happen without me realizing. And when I’m fucking you I can control it. Generally it’s considered poor etiquette to knot someone without any warning.”
“I suppose I should be flattered, sort of.” Stiles stared at the mess. The tube was split beyond repair and the mold that was still surrounding Derek’s cock had a large tear in the side of it. Come was dripping out onto the kitchen floor, mingling with Stiles’ which had landed there too. “Huh. Well I guess we’re going to need to buy another cock-casting kit.”
Derek sighed as he carefully pulled the mold and what was left of the tube off his cock with a wet, squelching sound. “Really? Can’t you just take photos of it like most people do?”
Stiles pouted. “But I really wanted a Derek dildo.”
Derek stood and put his arms around Stiles, nuzzling his throat and rubbing his stubble over the soft skin in the way that he knew Stiles loved. “I’ll come and visit you every weekend,” He promised. “Then you can have the real thing.”
“The real thing is better, but I still wanted one.” Stiles turned his head, seeking Derek’s lips and kissing him softly. Then he stepped back and surveyed the disaster that was the Stilinski kitchen. “But now we need to clear this up because my dad’s kitchen looks like an explosion in a meth lab, with added jizz.”
Derek laughed, then reached out to touch Stiles’ cheek with the pads of his fingers. “If you really want, we can try again with another kit.”
Stiles’ face lit up. “Thanks.” Then he grinned wickedly. “But maybe we should give the panties a miss next time?”
Derek cleared his throat, embarrassment warming his cheeks again. “Yeah, maybe that would be for the best.”