a term used when a member of one sex spontaneously spends the night with a member of the opposite sex in a non-platonic way, usually following a night of bar-going or after a fabulous date.
You have no preparation....no toothbrush or extra clothes. You have to wear what you wore out the night before. You should also add that you usually get dropped off in a random parking lot where you left your car, if you can remember where it is. (see term 'walk of shame')
by Vanessa * Leigh June 17, 2005
The definition of a platonic-overnight stay is not the meaning of this word. Shacking means that an unmarried couple is in a sexual relationship and they live together

See also playing house.
Me: Mom, where's Joseph? Haven't seen him in awhile.

Mom: Oh, he's shacking with his girlfriend.
by Canned Coolwhip February 12, 2011
When a slampiece spends the night with her frat-daddy in his cold-air. Usually does the walk of shame home in at least one article of his clothing.
Girl 1: Hey where were you last night? I didn't see you in your bed.

Girl 2: I was shacking with my frat-daddy!
by AXO Princess January 6, 2011
A device known as a vape.
Guy: I just hit the shack, shit got me domed.
by Ayecallmejohnny September 20, 2018
shack v. intr.

to spend the night at someone's place, sleep in the same bed, and mess around. sex may or may not occur.
"I shacked with him four nights last week, so I think things are getting pretty serious."
by jpatt December 24, 2004
Slang used nearly exclusively in very Southern California to mean the headrush feeling of nicotine
A: Bro, pass the Juul
*A rips Juul*
B: You shacked bro?
by E-ratic Magician March 8, 2019
A location, usually a bedroom where a group of mates hang out. 'The Shack' is characterised by being a complete mess. A night at 'The Shack' generally consists of extensive drinking, smoking and chundering. 'The Shack' provides a relaxed environment for topics such as politics, racial issues and how awful Morrissey is to be discussed at length. Constant visitors of 'The Shack' are said to experience increasing shakiness and unsteadiness. Occasionally the shack's intoxicated host will rinse out some tunes on his flute, much to the members' applause.
dude1: whats happening tonight?
dude2: heading to the shack
dude1: ah! so we are in for a night of chundericious fun then!
by a patron of the shack January 1, 2008