I'm actually more into cock fun and sucking with guys, but I do get asked to fuck men. If he's "straight" or married it's definately not just another ass to fuck. There is a feeling not of overpowering, but sharing in a "straight" man's power when you fuck him, especially if he's new to that. I don't like to generalise, but bi or married men seem more participatory, more into the idea of using their ass to give pleasure as well as getting off on a prostate massage. It's as if having fucked pussy, they realise the "receiving" role is not really "passive".
When I fuck a gay man, I often feel like I'm doing him a favour, or having to do all the work. With a straight/married/bi/whatever guy, it's more of a joint enterprise. Maybe I'm just meeting the wrong gay guys! | 
