"You like that thought?" Stiles asked, turning his head just slightly towards Derek. "You like the thought of us being watched?" Because yeah, he could add that to his list of kinks no problem. He'd very happily let other people watch Derek fuck him, as long as they didn't touch. "And you know I've always thought your car was sexy. I really want to do things to you in it, but on it would be just as good."
Stiles purred happily at the lovely mental image he was being given, the sound changing quickly to a sharp gasp of pleasure when Derek pushed himself so blissfully deep, when he rubbed himself just right inside of Stiles.
"Fuck- fuck, maybe I need to get a cock ring. Keep me hard inside you-" he'd seen some online that were meant to be similar to knotting, that could be inflated when you were inside your partner that did the same thing. He could be hard inside Derek, Derek could feel the stretch, and Stiles could have orgasm after orgasm before he loosened the ring and filled Derek up-
Maybe he'd look it up on his phone when they woke up again, show Derek, see how he felt about it.
"You ever- have you ever been knotted before?" he breathed, because the thought of being able to do that, for Derek to experience that for the first time with him- that was ridiculously hot.
The thought, coupled with the sudden stimulation at his nipples, made Stiles cry out again, his muscles clenching around Derek's dick as it slid so easily in and out of him. And then Derek's hand was on his cock and it was going to be too much, slow as his mate was going.
"Yes- yes, want to see, yes-" he panted, knowing how good it probably looked. That had always been one of his favourite parts of porn, watching the person on the bottom be penetrated, watching a cock push in and out.
"Can you- you see me stretching for you? I can feel your knot growing, can feel it opening me up-" Stiles whispered, heat spreading up his thighs and into his stomach, his orgasm not far away. But he'd hold out until Derek couldn't move anymore, until they were tied together again. "I love it like this. Love it slow so I can really feel you," he breathed.