Its when your fucking a girl and you look down... AND ITS YOUR GRANDMA!!!!
Guy 1: *fap fap fap fap* "Ah damn girl hell yeah... AH FUCK ITS MY GRANDMA!!!!"

Guy 2: Damn thats quite the big surprise!
by Mrdriller6969 October 21, 2010
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its a sex gesture where you think ur fucking your girlfriend... but ur really fucking ur grandma....

originated: cooper b
Cooper: DUDE i was with my girlfriend last night and we were doing it, but then i looked down

Trenton: AND IT WAS YOUR GRANDMA

Cooper: THE BIG SURPRISE

Trenton: OMG THE BIG SURPRISE
by eagermcbeaver October 21, 2010
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When a guy shows up at a girls house unannounced with his cock hanging out!
Chad : Hey girl what's up!
Keirsten : Ohh Baby What A Big Surprise!
by JDawg 316 March 6, 2016
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Big Corn Suprise - When you have a bowel movement and you see corn in it BUT you dont remember having eaten any corn recently. Also known as a BCG.
Big Corn Suprise - Refers to the phenemon of having a bowel movement and seeing corn in it BUT not remembering having eaten any corn recently. Also known as a BCG.

Joey had a Big Corn Surprise last nighr but soon remembered having Shepherds Pie a few days ago in the cafeteria.
by Zsazz2023 May 12, 2023
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Big girl surprise is what you get when you undress a very obese woman , it's the bacteria that grows in their folds and crevices of fat and the cottage cheese that comes out of their vagina by having a yeast infection.
Yeah bro I hooked up with this fat bitch last night and she gave me the big girl surprise!!
by 1Bigggmike1 April 3, 2023
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