The Act of strapping a dildo to the front of your car, and ramming it into the anus of another person from behind.
Last night, a car snuck up from behind me and gave me the Good old fashioned Shannon Butt Surprise
by Bob statutory December 31, 2021
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Also known as the BGS, this is a loving sexual act in which the giver urinates up the butt of the recipient.

BGS tournaments are also known to occur in some parts of the United States, though the rules of the tournament aren't well known.
I couldn't believe the sensation brought on to me after receiving my first BGS.

After years of BGSing, I have a permanent limp.
by Dave February 12, 2004
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Joey: SURPRISE BUTT SEX!!!!! *dry hump's yuig*
Yuig: Joey, with you its never a surprise...
by motherly love January 18, 2010
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When a girl is having sex with a guy doggy style, going at it really hard and fast and one of the times his penis comes out as hes putting it back in he misses the vagina and puts it in the butt!
Girl 1: so how was jimmy last night?

Girl 2: girl he was good except he was fucking me doggy style and he gave me some surprise butt sex! And now im sore cuz jimmys got a big dick

Girl 3: ooh girl you so lucky!
by leslieann918 February 3, 2011
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An unexpected anal sex. Can be used to surprise someone painfully (best method for rapist).

You may see some unpleasant results for surprising them.
PARIS: Hah you can't surprise me painfully...
MAN: Oh yeah?
*Shoves the penis in the anus*
PARIS: HOLY SHIIIIIIIIIT!!!!!!!!!!!!!
MAN: Holy Fuck....

surprise butt secks
by MrXman September 20, 2010
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