Okay, here is something I don't get, of which is related to the threesome issue. If you're heterosexual and moderately successful at it, you've encountered many lady parts, such as breasts and labica's (or whatever they're called). After a while, you'd think the heterosexual would say "you know, I have frolicked with many breasts and labica's, and now I have grown weary of those parts, which are fairly similar from lady to lady, even though there are charming differences to be sure." And from there, you'd think they'd conclude that it would be fun to frolic with the parts that other guys have (do not need to name them). But that doesn't seem to happen very much. I wonder why it doesn't happen more?