I don't know about the whole good-in-bed question. Because yes, definitely, after a while together they'd both be phenomenal (because of the aformentioned tongue/hand/focus points, and the intimacy, and the familiarity with each other's bodies and likes and dislikes and turn-ons). But right off the bat? Especially in those stories where they've only ever been with women? I'm not sure if it's more realistic to say that the sex wouldn't be that great, but I think it's certainly believable to imagine their first time as awkward, weird, and maybe a little desperate and unsatisfying. And I kinda have a kink for that, because then you get to see how things change and get better. I really liked what Kat did in "End of the Road" - she acknowledged that, yep, sex was sometimes phenomenal, but sometimes Fraser had a hard time getting outside his own head, and Ray got easily frustrated and discouraged, and a lot of the time the sex just fizzled. The story is, yeah, a downer, but that element of realism in their sexual relationship made it even more compelling, at least for me.

But then...*sigh* I'm the one writing a 45+ page rentboy!Fraser story and there is still no sex. So perhaps I need to work on imagining Fraser as a much more sexual and erotic character. It'll be tough, but I'll work at it.