The answer to #4 can depend on whether you're hiring him for a top or a bottom. Since I hire them only to bottom: (a) if I turn him on enough that he cums in an apparently natural way, all the better, and I'm very complimented; (b) if he doesn't cum, or doesn't even get hard, it doesn't detract from the experience for me, but that might be just the way I am; © I've had a few guys cum, or try to cum, with what is pretty plainly unnatural effort--I'd rather they didn't.