Gym Snail

The sweat mark left on gym equipment by your ass when you get up

Dude did you see the gym snail that guy left on the shoulder press machine?

I have to put a towel under my ass, because I am scared I am going to leave a "gym snail" on the equipment!

Gym snail

A person who goes to the gym and doesn't wipe down their sweat off of the gym equipment

I went to the gym earlier and a gym snail had used the equipment I needed, gross.