Top Definition
The motion, and sound of one's balls swaying back and forth, and slapping a male's thighs when he is running up or down stairs with loose fitting shorts on.

NOTE : Not to be confused with Oh-my-god-that's-sicktapsis, which is when Meat Curtains hit thigh.
"I had a serious fit of demotapsis this morning. It was so bad that it woke my mom up!"
by Bzur December 21, 2009

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

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