I'd love to find someone willing to play multiple girls against one of my guys. Not at the same time but in something revolving around him being a bad boy and cheating on her with either her friends, her sister(s), her mom, or anyone else really as long as they are somewhat close to make it wrong.
I'd imagine the girlfriend will be a bit of a prude and his 'extra' girl will be a filthy freak and would love to play him against both. Dealing with his desire to actually want to love his girlfriend and try to guide her in to doing some of the nasty stuff his other lady does and of course him unable to stop himself when the nasty girl wants attention.
Up for playing this out just about any way and letting it slowly build to something. (Does he end up with the good girl? The bad girl? Neither? Does he find a way to get a threeway? etc etc).
I'm up for PBing just about anyone as well as long as long as it makes sense in the line! (Older couples, high school couples, etc!)