Call it Everything You Always Wanted to Know About Anal Sex (But Were Afraid to Ask).This unbelievably raunchy gay variation on American Pie follows four high-school seniors who vow to lose their virginity—where the sun never shines, of course—before the end of the summer. Minor-celebrity cameos (Lypsinka, Richard Hatch, Boy Meets Boy’s James Getzlaff) are as plentiful as the gross-out gags involving enemas, butt plugs and gerbils. But Graham Norton as a leather daddy sporting a two-foot prosthetic penis? That’s just scary. (Opens Fri; Quad. See also “Class action.”) — Tom Beer