For all the supposed crassness of their gender, in my experience men are often incredibly giving in bed. "My experience" is always skewed, but most men I've been with view the stimulation of their own bodies as a side attraction, as something of an "eh, getting my cock rubbed is fun and all, but I can do that anytime." Most of the guys I've been with, good and bad, have been all about my physical stimulation.
The catch is, they may not be giving something you want to take. A guy saying "hey baby, let me finger you, let me go down on you, let me make your fantasies come true" is just as skeevy if he's not taking no for an answer, even if he's not being physically selfish.
Maybe this is why, when you go into a sex toy store, there'll be like eighty varieties of dildo and vibrator and three or four really sketchy-looking male stroker thingies.
Maybe it has to do with the perception that female sexual experience varies tremendously in quality, while male sexual experience is an on/ohbaby/off sort of deal.
Maybe it's a male gaze thing, where thinking too much about male physical experience and response would be, in some utterly unfathomable yet horribly plausible way, gay.
Either way, it puts me in sexual situations where the toughest performance expected of me is "have lots of orgasms!" and, gosh, I can't pretend to be too broke up about that. I hope this isn't one of those situations where I was supposed to be going "no, no, after me" all along, but I think it isn't. (Particularly with dominant men, who don't exactly have trouble telling me what they want.) I think I really do live in a world where a lot of guys' sexual desire manifests as wanting to give me pleasure.