Top Definition
When you shart and jizz at the same time.
Me and my GF just got back from Bernies Burritos and things got a little steamy in my car and in mid thrust I had a Mount Saint Helens. She then proceeded to lick my butthole.
by Merrick and Smitty January 28, 2010

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A sex act in which a male pours pop rocks into a female's anus, pours in some cola, and has anal sex with her without a condom.
I gave a girl a Mount Saint Helens last night. It was great until it erupted everywhere.
by evilempire August 15, 2010

The Urban Dictionary Mug

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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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A super intense ejaculation of sperm. An explosive orgasm, where hot sperm shoots out like a lava flow.
" I met a really hot Geologist last night. We were making out, and I got hard enough to cut diamonds. I took her back to my place, and I explored her cave for awhile. I totaly Mount Saint Helensed! Holy Schist,She got my rocks off. I had a gneiss time.
by Big Foot In A UFO July 08, 2004

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