Per request, here are some caps of Ryan Merriman in "Wild Cherry", which has a good, if only PG-13, embarassment nudity scene where he gets stripped down in a pool with his other friends. Personally I would have killed for at least one butt shot of the nicely muscled star.
I also scrounged up some more pics from around the Web, with a lot from my goold old friend xyz of Scenes of Male Skin. (If you ever want a clip, it's there!)
Check 'em out in my Ryan Merriman gallery.