The best thing a guy can do in bed with me, bar none, is like what I'm doing to him. There is nothing you can do with your fingers that feels as good as a really sincere moan of enjoyment.
Yeah, most everyone likes getting laid, but there's a difference between guys who don't think it's a bad way to spend an evening, and the surprisingly small proportion of guys who are fucking into it. Expressiveness is obviously a factor, but I don't think that's all there is. Most guys are fans, but some guys just love sex.
Those guys are the best.