Something about a woman taking the initiative turned Dean on; he'd never really known why. He saw what she was doing with her fingers, and grinned. Well, if she likes it like that, works for me. He'd been hoping - hell, it was why he'd brought the lube over - but this way was nicer. This way, they didn't have to have a "So, do you like anal?" conversation. Those were almost always awkward.
He scooted back a bit, keeping his fingers working at her and moving his mouth. He bit gently at her finger to get her to move it away, and replaced it with his tongue, making the tiniest of stabs. It wasn't something he did all the time, but it was God. She'd basically invented this.