If Stiles had smelled of distress, or worse, if he'd smelled like he had two-- three days ago, when he was lying in Derek's bed crying, his scent turning sour, he would have stopped like he had then. That scent wasn't there this time, it was warm-happy-delicious and Derek could not stop pressing his face into Stiles' skin to breathe it in directly from the source.
He grinned for half a second when he heard and felt Stiles coming again, a fresh punch of sweet pleasure in the air, and growled as his orgasm chased his mate's. Exactly as it should have. And he knew, knew Stiles could come at least a few more times before they were both exhausted.
"Humans would be able to tell," Derek rasped out. Anything with a sense of smell keener that would know that they'd been occupied, as new mates often were.
Nuzzling into the constellation of beauty marks across his shoulder and throat, his arm still tight around his hips, Derek rolled them onto their sides carefully. Being knotted was a vulnerable time, not only due to the knot that would hurt both of them if he was pulled free, but all of his senses were focused on Stiles and his ability to move hampered if anything happened.
But they were safe here. And he felt that little away motion when Stiles rocked back, knew what it was, and nuzzled his shoulder, his free hand splaying over his chest. Maybe something else to focus on would help. "Probably," he answered as his palm slid over his skin, the edge of one claw teasing over one of Stiles' nipples.
"You do," he added with a low croon, unable to stop the little jostle of his hips, wanting to feel Stiles coming on him again. "Smell and taste. Want you to come again baby, got more to give you." More to ensure that Stiles would get pregnant. The red was still present in his eyes, but his teeth began to slowly recede, his instincts for his mate beginning to feel satiated for the time being.