Example: Girl 1: You coming to the movie with us?
Girl 2: No, she's coming to the club with us!
Girl 3: Umm, I need to think about this, I don't really want to have to choose.
Girl 1: She's just trying to sit on the fence.
Example: Penelope was a lovely girl, so Shaft gave her a call. “Sit on my fence” he said. After all, the newly erected fence was newly varnished, and he knew she’d appreciate it.