Kingdom Hearts, Sephiroth/Riku, drowning in you.
It was somewhere between Sora poking at the spiny fins running the length of his tail--"So what are you?"--and Ariel pointing a shaking finger not quite past Riku's shoulder and squeaking: "Sea serpent!" that he figured out he was weird even for Atlantica. He'd turned his head to look over his shoulder--optimistically, as it turned out--and didn't even have time to reassure them that it was just Sephiroth slicing through the water toward them before he was caught. In silver coils much larger but very, very similar to his own.
The others scattered, but he didn't really blame them. Ariel would later blushingly explain it as instinct, and Sora would mention something about how sound carried in water, and Kairi...well, she'd had Sora's hand clapped over her eyes at the time, but that was probably for the best.
Fucking on the wing sounded more daredevil than it was with a will as strong as Sephiroth's to hold them up. It was balance and freedom and trust, always a little precarious until he settled himself just so and rode the man, the whole thing his show from beginning to end. He liked it like that, suspected Sephiroth liked it too.
Being wrapped in what felt like miles of serpent coils was entirely different, but he wasn't exactly complaining. It was weird not to have legs, but his own snaking tail knew just what to do, winding tight around Sephiroth's, scales a shade darker but just as smooth. The man's spiny fins stung when they raked him in their enthusiasm, but it felt weirdly good, like the dig of nails or the sharp nip of teeth.
Sephiroth's hands slid warm and slow down his back to cup the sharp blades of his pelvis, thumbs stroking where skin shaded into scale. Reaching up to push aside the drift of long silver hair, Riku hummed a faint groan as Sephiroth's mouth descended on his neck, and oh fuck, when had their tongues gone forked?
Heavy coils clutched him tighter as Sephiroth moved against him, holding him caged and close. Riku's breath wanted to hitch--too good, and since when did he like being pinned?--but there was nothing but water all around, nothing but the wordless demand of Sephiroth's mouth to drown in as he knotted himself like a constrictor and thrust, scales against scales and heat against heat, hands gripping the wingless angles of Sephiroth's shoulder blades.