It wasn't like cock sucking was his favourite thing to do in the world - not even close, actually. Rodney was rather fastidious about bodily hygiene, and he wouldn't go down on John unless he'd taken a shower first. It was something that drove John a little nuts, especially when he was swept up in the moment. For the most part, Rodney really didn't care; he wasn't letting John stick his cock in his mouth without washing first, no matter how hot (and hot and bothered) he was.
And, of course, his jaw got sore quickly. John's cock was big, and it was hard to suck him all in without teeth catching on sensitive bits or triggering his gag reflex - often both.
There were a lot of other things they could do - things he really enjoyed, things that made John come, and come hard. All things being equal, Rodney could go quite happily without sucking John's cock for the rest of his life.
The problem was... all things were not equal.
When they'd first started doing this thing, Rodney had been all over John, sucking, licking, kissing, exploring - it had been less about figuring out what John liked than about feeding his appetite to touch!claim!own! It had, however, resulted in discovering a number of things John liked, and he'd come up with his own Sheppard's Top 5 list.
For example, John enjoyed having his nipples played with -
...John shuddered beneath him as Rodney tongued the stiff nub of flesh.
"Fuck!" he whispered, arching into Rodney's mouth.
"You like that, huh?" Rodney asked, smirking down as he drew a fingernail across the damp nipple.
"Oh yeah," John replied, then gasped as Rodney's teeth gently latched onto the other one.
An odd one that Rodney had discovered completely by accident - John really liked it when Rodney licked the inside of his arm.
Rodney had started with a simple kiss on the palm of John's hand, lips grazing his wrist, and was surprised by the explosive reaction it elicited. Intrigued at how the simple caress made John squirm and thrash beneath him, Rodney rolled him onto his back and lay across him, pinning him in place.
Grasping his arm firmly, Rodney used his mouth to map a meandering trail of little licks, nips and kisses over the delicate skin until he reached the crook of John's arm. He focused all of his attention on that tender crease, alternately dragging the tip of his tongue along it and then blowing across the damp skin.
John groaned and shook and Rodney took a moment to kiss him sweetly before rearranging himself, to repeat the process on his other arm.
John loved to leave marks. It really turned him on to be able to leave bruises -
John nuzzled in behind Rodney's ear, making him shiver as he nibbled and licked at the skin of his neck. His arm was wrapped around Rodney's stomach, holding him firmly in place.
There were a collection of minor bruises on his shoulder and torso from a quick escape/run/tumble down the side of a hill earlier in the week. John's mouth moved to a small patch of unmarred pink between the contusions, and carefully worried the piece of skin between his teeth. Rodney hissed but held still as the sharp sting was followed by a soothing lick, repeated again and again as John placed a network of marks among the ones that were already there.
Rodney could feel John's erection, hard and hot, against the small of his back, and he moaned. "Fuck, John! Just fuck me already!"
"Soon, Rodney, soon," John promised as he lowered his mouth to Rodney's skin once more.
And wow, John went off like a rocket if Rodney bit him on the back of the neck while they were fucking-
He thrust forward, John's hips snapping back to meet him, and he was close, so fucking close!
"God, John," he moaned, one hand grasping John's hip, the other wrapped around him, fingers curled up over his shoulder. Rodney's hand tightened, pulling John against him as he settled on his heels, dragging John to sit on his lap, driving Rodney's cock in deeper.
"Oh, oh, Jesus, Rodney-" John gasped out, head falling back against Rodney's shoulder. Rodney licked the shell of his ear, kissed his neck, then bit down hard as his orgasm slammed into him like a freight train. He felt John's body seize and convulse around him, felt warm sticky wetness splatter across John's chest and his arm, and realized that he'd made John come without touching his dick, and he was so going to do that every fucking time he could for the rest of his life -
But of all the things that John liked, of all the things he did that got John off, John really loved it when Rodney blew him.
"Jesus, Rodney," John croaked out, eyes slitted as he watched his cock slide in across Rodney's lips. "You're like the best porn when you do that, oh fuck, yeah!"
Rodney didn't feel like the best porn. His jaw was sore. His knees were sore. The angle wasn't horrible, but it wasn't great. But John was looking at him like he was the hottest thing he'd ever seen. John was licking his lips, and panting, and mumbling shit like, "so fucking sexy" and "porn star mouth" and "want you like this all night" and Jesus, if it wasn't the biggest fucking power trip to see John so out of control, he didn't know what was. It was like he was on drugs, because John, Colonel Taciturn himself, just couldn't seem to shut up, praises for Rodney's sexy mouth mixed in with dirty talk and random moans, and damn it! He might be crippled tomorrow if he didn't get off his knees soon, but it was so worth it.
John reached out with a shaky hand, sliding his fingers into Rodney's hair to grasp it firmly before his hips started to thrust, Rodney's sure fire warning of impending orgasm. He tightened his grip on John's thighs and tried to relax his tense jaw.
"Fuck!" John's hips stuttered and then Rodney was swallowing around him, putting up with the taste because, Jesus, the noises John was making were incredible! And then John was pulling him up on the bed beside him, kissing him deep, tasting himself in Rodney's mouth, and if Rodney hadn't already been hard enough to pound nails, that would have done it right there, because fuck. John was sucking on his tongue and it was filthy, scorching hot.
John pulled back from, sucked on Rodney's bottom lip for a moment, then released it. "Gonna suck you now," he said, a little glassy eyed, a little breathy, and Rodney felt him, warm and solid against his belly - holy shit!
"You're half hard again already!" he accused, half annoyed, half impressed.
John grinned at him as he shimmied down between his legs. He peeled Rodney's pants off, mouthing him through his boxers before pushing those down as well, and Rodney decided that it was possible he'd have to re-evaluate. While sucking cock wouldn't really ever be something he enjoyed, making John lose his mind was. If he split the difference - it might not make his personal top five, but maybe his top ten...
"Oh, god," he gasped as John shouldered between his thighs, grasping leg behind the knee and pushing up and open. Top ten for sure was his last lucid thought before his ability to think went abruptly offline as a hot, wet inferno enveloped his cock.