When you finger a girl, and then stick your finger in her ear.
"I didn't give her a wet willy, I gave her the slimy slug"
Little globs of spunk left on wall of bathtub after mastubating in the shower.
Awww man, i almost slipped and fell in the tub because jermy left tub slugs in the shower.
A flat surface at about seat height, that despite being very uncomfortable is used as a bench by students. Usually whist eating.
Person 1: "Are you on a break?"
Person 2: "Yeah, slug bench?"
Person 1: "YEAH!"
Some bum who thought the "s" in the word "its" was too common and wanted to be different.
Working.
Especially: putting in the hours to earn money.
Similar to grafting.
A: "Been out enjoying the sun today mate?"
B: "Nah I've been milking the slug all day"