Undercover opp

A undercover opp is a person that acts cool with somebody but does sneaky sh*t to the person their pretending to be cool with.

I don’t trust kevin he’s cool and everything but he seems like a undercover opp i heard he finesse Chris last year.

by Thatboy003 July 28, 2020

Sans undertale

A big black cock

Omg You have a Sans undertale.

by poop Josh February 8, 2022

The Undertale effect

Once something popular releases, the community and any content made about it WILL degrade and become worse overtime.

"hey have you noticed the twitter community on welcome home keeps getting worse?"
"That, my good friend is the undertale effect happening in practice"

by AmnesiaPen May 6, 2023

undertongue

Historically known as "the vagina of the mouth," this area has gained recent popularity among "headventurers" for remaining constantly wet and sensitive.

Headventurer:"Sheila, lets try something new"

Sheila: "oh ya, put it in my undertongue"

by Gorilla Adam December 6, 2009

undercover fart

when a girl farts when your in a car, house.....ect. and all you smell is a funk in the air and the source is unknown.....but guess what thats your girl ninjaing one out

i was laying in bed one night and all i smelt was a strange odor i looked over at niki and asked about her undercover fart....she laughed and admitted to it

by Mateo El Feo January 11, 2009

Undercover Sub

n. a long, submarine shaped turd that is crapped out before, during, or immediately after sex....beneath the bed sheet covers.

The undercover sub slinks, slithers, and slides across the sheets until it comes into contact with one's sexual partner...causing a multitude of reactions which may include, but are not limited to: excitement, anger, fear, frustration, confusion, bewilderment, angst, mild and/or severe depression.

Last night after I did it with Janie, I swear I heard her shart. No sooner had I smelled the crap, then an undercover sub appeared out of nowhere...spreading across my leg like a wet, stinky rash. It ruined the new bed sheets!

by Dr. Josephus May 27, 2011

undertake

To overtake a vehicle on the wrong side. Dangerous, and illegal in many countries, especially Germany where Autobahn (motorway/freeway) laws are extremely strict. Favourite activity of audi man, usually at dangerous speed. Audi man will also cut you up afterwards.

EG, in the UK where one drives on the left and overtakes on the right, passing on the left is undertaking.

by oracle January 31, 2005