The more Sephiroth learns what Cloud likes and keeps doing it, the less aware Cloud becomes of his own quiet moans and heavy panting. Even when he isn't holding back, it seems he just isn't all that loud, but his body's shuddering tension and the way he squirms and arches his back speak for him, too.

He looks down at Sephiroth with slight alarm, and then a touch of awe as the man's effortless strength keeps him still when his own will can't. "S-sorry..."

It turns out to be a good call on Sephiroth's part, because Cloud's getting steadily closer to climax and can't control his hips' sporadic attempts to buck up against those strong hands, heels digging into the ground and eyes squeezed shut again.