The first time he says it, it’s their very first foray.
It's not the pain; he's sure as fuck had worse. The sting of her hand is pleasant, for the most part. She's laying into him and his back is arching and his cock is jumping and he knows if it weren't for the cuffs around his wrists he'd be covering his ass with both hands, an eight-year-old troublemaker getting belted by his dad. Thank God for the cuffs.
She's talking the whole time, words just loud enough to be audible above the sound of skin on skin and ragged breathing, words like 'filthy' and 'whore' and 'bitch,' and they're such good goddamn words. She bites off every syllable and spits out every 'fuck' and it's just fuel to the fire.
He says it because suddenly, one hand sliding lovingly down the slope of his back and the other stinging his ass again and her quiet obscenities in that crooning voice - suddenly it's all way too much. There's a tension winding in his balls and all he can think is fuck and she hasn't even touched my cock, and the word 'mercy' comes tumbling out of his mouth before he can stop it.
Her hand aborts on its way down, and the hand on his back comes creeping over his shoulder to pull his face off the mattress. Her eyes are concerned, but all she asks is if he's calling it quits already, and if 'the fuck word' was too much for him.
He sits back, smarting ass against his heels, and tells her she's the worst girlfriend he's ever had. She jerks him off with her whipping hand, warm from use, and leaves him cuffed. It takes him forty-five minutes to find the key and get loose, and by then, she's already gotten off in the shower twice. He heard every minute of it.
The second time, he's tied up spread-eagle with her straddling his face, and he's never looked forward to anything more in his life.
He buries his nose in her cunt, pushes his tongue deep, grazes her with his teeth, sucks at the hood of her clit. She's teasing her own tits and murmuring, sounding for all the world like she's praising a surprisingly well-behaved dog. She's wet as fuck, but then, he knew all her nonchalant disinterest was just fronting.
Without his hands, there's less precision; he's pushing her lips apart and pressing his cheekbone there to open her up, wallowing his entire face against her. He's lightheaded. She's bearing down on him with her hips, demanding more. He obliges, just so he can remind her later that she said 'please' and it actually earned her an orgasm. Not that he thinks she'll say it any more often.
His own hips keep lifting, arching off the bed, but there's nothing there for him. He's leaking precum, tensing his thighs to try to squeeze them together. Her knots hold fast.
She's almost there - he can tell by her hands in his hair and the way she fucks his face, like he's not even sentient down there, nevermind trying to breathe - when she says it, clear as a bell: 'give it to mama.'
And he knows - he fucking knows she's baiting him, he knows in his fucking bones, but it's like a massive nuclear boner meltdown the instant their mother enters his head, and there's no containing it. He throws his head back, free of her tightening thighs, and yells 'fuck' and then 'mercy,' and he swears she laughs before she climbs off of him, looking innocent as you please.
She unties him under verbal assault and watches him stalk into the bathroom, and he takes the world's coldest shower while he listens to her harmonizing with her Hitachi.
The third time is clear overzealousness on her part, and she even apologizes when he picks himself up and slinks out of the room.
He's tied at the ankles, kneeling on the floor with his legs spread slightly and his hands bound behind him. She's seated on the arm of the couch behind him, out of sight, but when she clicks the remote on, he can feel it in every inch of his body. The vibrations clamp around his cock and start pulling him up, up, up before she turns it down again to a low rumble.
She plays with him, building him up and letting him down, giving him thirty seconds to pant desperately and hurl epithets at her and then cranking it up to eleven. His words dissolve into cries and moans and inhuman sounds. She turns it down. He breathes.
His hands are on his heels, balancing himself as he arches his entire body upward, straining every muscle at the verge of an orgasm. The vibrations are moderate; not enough, but too much to ignore, and he's so ready to be done. She turns it down. He makes a sound that's a kissing cousin to sobbing.
'Please,' he says, and she wants to know please what, and he should really be more specific about these things. He tells her to please fuck herself, and she rolls the dial up steady until it hits the top.
No sooner does it than his whole body folds and he goes down on his side, writhing and thrashing and maybe he's crying, and his cock goes from absolute bliss to an electrified terror of overstimulation in the span of six seconds. He gasps and tries for words, but it's another ten seconds before he finds the one he's looking for: 'mercy.'
The dial clicks off, leaving no sound but his heaving breaths, raw at the edges. His face is wet and hers is fond and apologetic when she leans into his line of sight. She tells him he's gorgeous, but he can't look her in the eye.
The fourth time is just plain embarrassing.
They're at dinner, a table for two at Taco Bell because they're both broke as fuck, but it's their anniversary and he figured it shouldn't go completely unrecognized that the two of them have managed to keep their shit more or less in a state of togetherness for three hundred sixty-five consecutive days. If it had been a leap year, he'd have sprung for Burger King.
He's teaching her Spanish again; what he remembers from school and what he's learned from the Taco Bell drive-through over the years. Her pronunciation is better than his, and it's inexplicably sexy. He's completely under control, just halfway to hard and trying to distract himself with his fiesta potatoes, when her hand finds his knee under the table.
She tells him in a convincing Spanish accent that she wants something to do with a library, and he doesn't quite catch all of it, but he doesn't miss her smirk as she walks her fingers up his inseam. He's glancing around the restaurant like a high as fuck highschool freshman. The public indecency police have got to be just around the corner. Her hand is on his cock. She's jacking him through his jeans in the middle of a Taco Bell.
When he starts feeling the buzz, he brushes her hand away, only for her to return with a vengeance. She opens her mouth on a smile and slides a spork in along her tongue, straight to the back of her throat, which convulses slightly.
It's around the time that she starts licking sour cream off her fingers that he finally caves and growls 'mercy.' She pretends not to hear him. He ends up saying it three times before she leads him to the bathroom and locks the door behind them. She tastes like hot sauce and victory.
The fifth time is his first time under a flogger.
They agreed when they started today that he wouldn't get off without her permission, but by lunchtime, he's painfully hard and the front of the panties he's wearing are damp. She's downstairs making tea. He seizes the moment, in a metaphor where 'the moment' is actually his cock.
With the door cracked closed, he's sitting on the end of the newly-made bed, gripping the bedspread in one hand and jerking himself feverishly with the other. His panties are bunched below his balls, the elastic straining up against them as a bonus. He slicks his palm with spit and works over the head, takes his hand off the bed to roll and squeeze his balls. Knowing she could come upstairs any minute makes him even more frantic.
When she finally does, it's with a sharp reprimand and a wicked-looking implement already in hand. This kind of punishment hadn't been part of the plan, but fuck if he's going to safeword without making her work for it.
She tells him to lie down on the bed on his stomach, and he does so with a snarky quip about getting off this way, instead. The bedspread is coarse against his cock. He wriggles his hips and is rewarded with a jolt of pleasure, then promptly punished by the fiery fatherly disappointment of God himself searing across his fucking back.
He invokes a couple of deities by name and pushes himself up, but the flogger bites again and his arms drop out from under him. His hips hit the bed and thrust forward in service of his cock. His back screams. He fucks the mattress and muffles his shouts of pain in the blankets.
Somewhere between strikes five and seven, he blows his load on the bedspread, but he barely feels it. It's on strike eight that he yells 'mercy,' his face still buried in his arms. She stops. In the moments of stillness that follow, the skin on his back prickles and burns. She kisses a raw spot; he hisses in pain.
The one time she lets him tie her up, she uses their safeword.
She's on tiptoe, her wrists above her head and her ankles spread apart. Her whole body trembles with the effort of trying to keep her toes on the ground.
Or maybe it's the vibrator.
He kneels in front of her, a feather teaser in one hand and a remote in the other. The bullet inside of her is cranked up to the max, but only for a second. Her cunt is starting to clench again, so he turns it off. Her chest heaves. She calls him a cocksucker.
He flicks the feathers across her swollen clit, watches her muscles jerk and her pussy clench again. She's right there, just one rough swat away from a fucking earth-shattering orgasm. She's been there for two hours, and her insults are starting to lose their venom.
Leaning in, he touches the tip of his tongue to her clit. She flexes her feet, trying to push herself onto his mouth, but all she does is lose her purchase on the carpet and swing back slightly. He catches her ankle bar to steady her and returns with the teaser, brushing it back and forth across her dripping cunt like Bob Ross painting some horny little trees.
He thinks he's imagining things when he starts buzzing the vibrator for a split second at a time, once, twice, three times, and he hears her gasp 'mercy.' When he buzzes it a fourth time, she cries it louder, and he stops.
She's shaking as he unlocks her ankles from the bar, then stands up to free her wrists. When her feet settle onto the carpet, her knees nearly give out. He catches her around the waist and asks if she's okay. She can barely stand.
She nods, hangs onto his shoulders while he holds her up. He's just about to ask if she wants to sit down when the room spins.
He hits the floor on his back, the wind knocked out of him, and she pins his arms with her knees, reaching behind her to unzip his jeans. Before he's even caught his breath, she's pulling his cock out and pressing herself down onto it. His attempt to reach for her is cut short when she grabs his wrists.
She fucks him until she seizes around him, 'god yes'es and 'oh fuck's all low and hearty in her throat. Then she lies down, her face against his chest and his cock still hard inside her.
'Mercy,' he breathes, and she lets him flip them over with a smile.