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Here’s the thing: Thanatos is big. And not just in the way he towers over Zagreus, allowing him to do so many lovely, unfair things— like smirking, just a little, as Zag struggles up on tiptoes to kiss him, or pulling Zag in just so he can rest his cheek upon Zag’s soft black hair.
No, not just that.
Sometimes, the lovely, unfair thing about Thanatos being big is how long it takes to slick Zag up and tease him open so that Thanatos can finally fit inside him.
Zag gasps out a desperate curse, arching and writhing with what little leverage he has. Thanatos steadies him with one hand on Zag’s thigh, and another on his own cock, keeping himself lined up at Zag’s slick entrance. He slips just a little bit of his cockhead inside, stretching Zag wide open until he feels resistance, and then slips back again, over and over, but he just— won’t—
“Shh,” Thanatos murmurs. His left thumb draws slowly up and down the soft skin behind Zag’s knee in a caress that is probably intended to be soothing, but instead turns his thoughts to ash and his insides molten. “Be patient, Zag. I don’t want to hurt you.”
It's enough to make Zagreus delirious with want. “Please,” he begs, low and hoarse.
Than’s gaze goes dark with unspoken promises. After a few more maddening, unhurried rolls of his hips, he leans down to nuzzle Zag’s chest.
“What do you need?” Than asks. “I could get my mouth on you again…”
“No, I need you now,” says Zag, feeling the way Than’s smile curls against his skin. “Need you— ah, inside… try… a bit more oil?”
Than kisses his belly, soft and reassuring, before straightening up to fumble with the bottle again. He pours it out and smears it between Zag’s legs with a lingering touch, sliding his dripping fingers just inside, before slicking up his own cock with the rest. He lines himself up, eyes intent on the place where Zag’s body is trying so hard to take him in, precious little bit at a time.
“Zag, maybe…” Than trails off, considering. “Switch with me. Let’s get you on top.”
Zagreus is only too happy to let himself be manhandled. Thanatos is always gentle and purposeful with his touches. It makes Zagreus feel so precious, so loved. Before he knows it, he’s throwing a leg over Than’s waist, sinking back to let the head of Than’s cock slide just barely into him from behind. Zag’s mouth falls open and his muscles go slack as he works himself back on it, letting the very tip tease inside of him, over and over.
“That’s it, love,” says Than, his voice gone low and intense in that way that makes Zagreus’s toes curl.
“We can do this,” Zag pants. The anticipation has his pulse pounding in his ears. He drags his hands up Than’s chest to thumb at his nipples, watching with lidded eyes as Thanatos moans and shudders. “I want it. I can take you.”
“I know you can,” Than answers hoarsely. “Go easy. Don’t hurt yourself.”
Zag doesn’t want to go easy. He rocks his hips back on a whine, loud and desperate, and underneath him Thanatos makes that low, wounded noise he makes when he really wants to kiss Zag, but can’t. Instead he gentles Zagreus with shaking hands, trailing caresses up and down his thighs.
Zag braces his arms on Than’s chest and writhes against the hot, insistent cock beginning to press into his body, feeling dizzy, wanting more.
“You can take me,” Thanatos whispers. “Zag, love. Just relax. Shh… I’ve got you. We can do it. Just be good and… relax… for me… oh—”
Finally, finally, Zagreus works past the widest part of the head and feels the rest begin to slip into him, the slow, inexorable slide as it goes impossibly deeper, and deeper.
Thanatos throws his head back and moans. “Oh. Oh.”
Zag’s mouth drops open on a shocked little noise. It feels huge inside of him, thick and hot and perfect, it’s so good, and it’s not even all in yet. He rocks back, leaning into the tantalizing, overwhelming intrusion. With every roll of his hips, he takes a little more in, sinks a little deeper into the sweet, molten pleasure of it. “Than. Fuck.”
Thanatos groans. His hands slide up Zag’s thighs to cradle his hips, trembling with the effort of not thrusting up, fucking into Zag the way he so desperately wants to. And the way Zag kind of wants, too, even if he thinks it might break him a little bit. Even now, it hurts a little, just enough to make him ache with pleasure and his whole body go involuntarily pliant.
Sure enough, after a few more unsteady rolls of his hips, Zagreus grunts, then laughs weakly as his wobbly legs finally give out. “Fuck, Than, I can’t move.”
Than pulls a pillow over his face with both hands and groans long and deep into it, and Zag just laughs harder.
“I know! I know, I’m sorry.”
“You like teasing me, don’t you?” says Than, but his eyes are glinting with mischief, and he counters Zag’s wide, joyful grin with a smile of his own.
“You know I do.”
Thanatos shakes with quiet laughter. Zag slumps against him, just to feel it rumble through his chest. “That’s okay,” Thanatos says, kissing his hair. “I’ve got you.”
He hauls Zag carefully up into his arms and rolls them over, pinning Zagreus against the mattress with his whole body, and Zag feels the delicious shift and stretch of it everywhere because Than’s still inside him, oh gods. Zag’s brow draws together as he gasps, pain melting into pleasure.
Than stills, eyes wide. “You alright?”
“Yes,” Zag moans, as centuries worth of affection blooms in his chest. Fond and frustrated and suddenly desperate out of his mind, he babbles, “fuck, I’ve never felt anything so— Than, please, move.”
“I’ll go slow,” Than promises into the crook of Zag’s neck. And secretly, the last remaining bit of Zag’s self-preservation instinct is grateful for it. It’ll take his body a minute to adjust to the stretch, he knows, even as Than begins to grind into him with measured little jerks of his hips, filling him perfectly. Thanatos licks up the shell of Zag’s ear and whispers sweet things to him, you’re gorgeous like this and I knew you could take it and you’re being so good for me.
It doesn’t take long at all for Zagreus to adjust to the shifting, velvety bulk of it. It’s overwhelming in a way that turns from too much to just right, so good, it’s perfect. Zag knows the minute his body fully surrenders because he feels the head of Than’s cock prodding sweetly against the deepest part of him, like they were made to fit together like this, and he can’t stop the shocked, needy sounds from spilling out of him anymore.
Thanatos is breathing hard, his brow drawn and his lips parted. “Zagreus,” he groans, rolling his hips a little harder.
“C’mon, c’mon, I’m close,” Zag says between ragged breaths.
Than bites down, muffling a broken moan into Zag’s shoulder. He brings one hand up to grip Zag’s thigh, keeping him right where he wants him. “Yeah?”
“Yeah— ah—”
Zagreus reels him in. Thanatos claims his mouth in a filthy, open-mouthed kiss, just as he slides his hand down between their bodies so he can stroke Zag off. Zagreus howls.
“That’s it,” Thanatos says, as Zag starts clamping down with his thighs and whining ah, ah, ah into Than’s ear. “C’mon… let go… that’s it, love. Come for me.”
Zagreus starts to come with a sob. Than fucks him through the waves of pleasure in steady thrusts, nudging his cervix over and over, until he finally stills, moaning low in his chest. Zag hears his breath hitch, feels every pulsing contraction as Thanatos spills himself deep inside.
Than eases himself down onto Zagreus, boneless and pliant, with a pleased little sound.
“So good,” Zag sighs. He reaches up to brush Than’s hair out of his face and lingers there for a while, running his nails up and down the cropped part at the back, until Than is humming contentedly against his skin. “You’re so good to me.”
Thanatos pulls back just far enough to look Zagreus in the eyes. “You’re, just…” Than trails off, but the way he looks at him, dazed and warm and reverent, speaks to his feelings perfectly. Zagreus adores him like this, loose-limbed, untroubled, and leaning in for endless soft kisses, all of his love pouring out of him as soon as their walls come down.
Once Zag has been truly, thoroughly kissed, Than pulls away and lifts himself up enough to watch Zag’s face as he slowly, gingerly pulls out. “Still alright?”
“Yeah,” says Zagreus, not quite managing to hide the way he winces as the widest part slips out. Than frowns, always worrying, no matter how many times Zag tells him he loves the ache of it, that the soreness that follows him around afterward keeps some deeply animal part of him purring with satisfaction. He wonders how long he’ll get to luxuriate in it this time. Hopefully a few days (or nights).
Zag surges up to kiss the frown right off Than’s face. “I love you.”
“I love you too,” says Than. And then he laughs, watching as Zagreus ducks down, scoops some discarded chiton off the floor, and starts cleaning them off with it. “Zagreus.”
“It’s better than using the bedsheets, you have to admit,” says Zag, before tossing his now-filthy clothes from the bed again. They land with a fwump. “We used a lot of oil, didn’t we?”
Thanatos heaves a put-upon sigh. “So we did.” He props himself up on the pillows. Zagreus arches, stretching, before fitting himself against Than’s side, and Thanatos wraps an arm around him in turn.
“I love this. Every time,” says Zag, with a lascivious eyebrow waggle. Thanatos hides his face in a pillow to muffle an embarrassed groan. “I love every bit of you.”
Thanatos doesn’t say a word. But Zagreus feels the lingering kiss Than presses to his hair, and he smiles, snuggling further into the warmth of Than’s embrace. Just enjoying the way they fit together.