When a guy and a girl are going out and the girl just hangs all over the guy. The guy doesn't care. The girl is useless and hangs there much like a keychain to a backpack.
girl: (hugs boy)
boy: meh

observing girls: god, that girl is such a keychain
by TangoMaureen December 10, 2005
The visible print made by a man's penis on the front of the pants. The phallic formation seen through a man's trousers, shorts, or jeans. See also DICK PRINT

Plural: keychains
We were too distracted by the keychain at the amusement park to really enjoy the roller coaster.
by q.wsmith March 31, 2010
In the act of threesome with two males and one female. A keychain happens when one male drives his penis in the females vagina, as the other male drives his penis in the females anus all at the same time. In which creates an effect of a keychain.
"Dude we keychained this bitch last night!"
by AccurateDefinitions4578 January 13, 2015
A prank in which somebody heats up another person's keys in an oven, then gives their unsuspecting victim the hot keys, causing surprise and a temporary painful sensation.
My keys! My keys are red-hot! Sammy, you rat! You weren't using the oven to bake salads! You were heating up my keys to give me the ol' Spicy Keychain!
by attractivecryingman December 16, 2011
A friend or acquaintance who is so cute, fun, witty and charming, that you want them to go everywhere with you.
"Chrissy you are my new keychain friend - I wish I could shrink you down and keep you in my pocket so you could go everywhere with me."

You might also use the term keychain before their name, such as "Keychain Chrissy"
by METRObliss August 16, 2009
The act of piercing the ring of someone's asshole and putting a key chain through the hole.
Bro, Jared had to get a rusty keychain because we bet him the Astros would lose, he screamed like a little girl!
by Jukke July 9, 2014
The act of shitting on ones keys after eating Mexican food
Hey John, you seem my keys? "Ya man, Marcus gave you the spicy keychain."
by Jack the shitter December 16, 2013