LOL Apparently I have too. I haven’t the foggiest notion what it is.
Hooking up is a term used to perform any type of sexual act (ranging from making out to intercourse) but it is done in a nonchalant way in which it can be for one night or for a week w/ the same person - it is sexual activity that is not taken seriously and is done for fun - it stops if you are finally considered to be “in a relationship” and committed.
I went to college during the creation and pop culture status of this terminology