Gainsville
A Gainsville handshake is when you walk by someone’s butt crack and you stick your finger up their crack like it's a greeting.
I did a Gainsville handshake with my professor and now he won't stop talking about it.
At the bar, I did a Gainsville handshake with a stranger and now we're friends.
My sister did a Gainsville handshake on my brother and now he's mad at her.