Women, it seems, just aren't used to guys not wanting sex. They rarely believe that no means no when it's the guy who's saying it. "One woman was like, You're kidding, right?" Tyler Barnett says. "And then for hours she tried to convince me to have sex." Another woman challenged his sexuality, he says. "If I acted that way, that would make me a monster."

Here's another double standard: Guys can be made to feel like dicks for withholding theirs. "There have definitely been times I wanted to turn down sex but couldn't bring myself to do it," says "Jeff," a 27-year-old grad student in New York. "We're socially conditioned to feel like pussies if we don't live up to the guys-will-fuck-anything stereotype. And because of this stereotype, women take sexual rejection more personally than men do."

"Being on the other side of someone going through the motions—I know how miserable that is," Greg says. "I'd rather go without."