Gainsville handshake - A Gainsville handshake is when you see a butt crack and you

A Gainsville handshake is when you see a butt crack and you stick your finger in it like it's a personal attack.

I did the Gainsville handshake on my brother and now he hates me.

I did it in the hallway and everyone laughed at me.

I did it on my crush and now we're both awkward.