When your having sex with a girl in the missionary position and she starts patting your bum cheek with one hand in an effort to make you go harder and faster. If she uses two hands then its commonly referred to as "double basketballing".
I was doing my thing all slow and sexy and she started "basketballing" me. I ignored it and then she started the "double basketballing" me into action. Fair enough.
Someone who jumps from one relationship immediately into another one.
Serial monogamists can not stand to be alone and often suffer from vast commitment and insecurity issues.
Because they jump into relationships immediately after the previous one has ended, serial monogamists typically don't take the time to reflect on their behavior or why their previous relationships failed; thus, they end up making the same relationship mistakes over and over again.
Person 1: Damn, Dustin already has a new girlfriend?! It's only been two weeks since he broke up with his fiance! I think he's a sociopath.