Top Definition
When you are standing next to a speaker at a concert or a party and the power of the music makes your trousers move.

Happens more with bass bins. Coined by DJ Nark.
The music was trouser-flappin' last night! Whopper tunes!
by theresamonsterintheparasol May 13, 2009

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.

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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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