A term used for anyone who goes into the pub at opening time and stays there until it closes.
A: Did you know that Jack’s been in the pub since half 12 and the pub shuts in 20 minutes?
B: Wow, proper si collins him.
Means self insert. The character you use and identify yourself to have sex with your anime waifu.
-I'm going to write a fanfiction between my SI, Jackard Bigchub Maximus, and Sagiri-chan.
+Do it elsewhere. Disgusting.
when one is typing the word "is" really fast and without thinking.
Short for Survival Instinct - the ability to know what to do to stay alive.
His SI stopped him from committing suicide.
si deez nutz
person one: how do you say yes in spanish
person two: si-
person one: SI DEEZ NUTS U STOOPID