When she rolls he obligingly rolls with her, coming to rest with his weight on one knee set between her own. In the course of moving he has to break their kiss (if they keep this up someone is going to manage to bite their tongue off out of the stubborn desire not to pull away) and he takes advantage of that to arch his back and work his way a little lower.

He has less patience for logistics than she has, maybe. At any rate she can work on shedding his shirt; he rolls his shoulders back and straightens his arms and occupies himself, pleasantly and shamelessly, sucking her breast right through her shirt, mouth hot and a little rough through the fabric.