Simpson? Look, we've already been down there tonight for a sisterectomy, a case of severe butt rot, and a leprechaun fight. How dumb do you think we are?
The act of dating a girl then to date her sister, known as the sister swap, if you swap back to the first sister, that is called the swap back. Though the definition of Sisterdistic would be equal to the swap back and back again.
Dave has beendating the Smith sisters on and off for quite some time now, they must be Sisterdistic.