Top Definition
The act of taking a #1 out of where you normally take a #2. It's a nice way of saying you have liquid diarrhea.
I ate some undercooked chicken yesterday and have been on the toilet twelving all day.
by Markatak November 28, 2016

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The act of faking being high. Pretending and acting like you're high when you really aren't.
Yo Josh is so stoned right now!
Nah dude he only took one hit he's twelving.
by youalreadyknow892 July 06, 2012

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To stand a motorcycle or other vehicle straight up in the air, front over back.
In motorcycle stunting, pulling a wheelie so high that the bike rests on the it's tail section is called a "twelve o'clock". The act thereof is called "twelving".
by ThrustinJ August 10, 2007

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The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

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The Urban Dictionary T-Shirt

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To 'space out'. Specifically the special sort of mental sluggishness brought on by watching television or any similar mental haze.
1: "Which street do we turn onto?"
2: "Huh? Oh, sorry. I don't know. I must have been twelving."
by Ninniane McFey October 11, 2005

The Urban Dictionary Mug

Lotsa space for your liquids.

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The Urban Dictionary Mug

Lotsa space for your liquids.

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The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

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The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

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The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

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The act of taking a solid 12 minutes alone and masturbating online.
E: Hey mate
E: you still here frend?
E: ..you been gone solid 12 minute, mate. You masturbating?

R: YES FREND I GOD DAMN TWELVING ALMOST DONE.
by kuack January 14, 2013

The Urban Dictionary Mug

Lotsa space for your liquids.

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The Urban Dictionary Mug

Lotsa space for your liquids.

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The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt