God, he loves this. Peter insinuates his hands under her shirt, rucking the hem up around her belly as his fingers quest upwards. She can probably feel him pressing against her through his trousers, already ready to go.

Feeling a tug on his jacket, Peter breaks the kiss and looks down in mild confusion. Seeing what she's done, he laughs and nips her lip, then extricates a hand from her clothing to reach down and unzip himself. His trousers are too tight to get things out in the open just by opening his fly, though, so he gives up on exploring her torso entirely (at least, for the moment) and hooks his thumbs in the waistband to push trousers and pants down just far enough to free his length.