The thing you hear before the FBI busts through your door and raids your entire house for loli.
*knock knock knock* FBI OPEN UP WE KNOW YOU'RE IN THERE
by Frank Grimey Grimes July 14, 2018
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When you listen to loli breathing as you jiggle your sausage.
Loli: Onii-chan, what is this white liquid in my pee hole?
FBI: *thump* *thump* *thump* FBI OPEN UP! *doors and windows blow up and rifles get fired rapidly*
by someunfunnyguy69 July 24, 2018
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A term for you to say to someone if something they do is out of the ordinary and/or frowned upon by individuals that use the internet.
Gary: I just got done masturbating to some really good hentai.
Jackson: Did it have Lolis?
Gary: Yeah.
Jackson: FBI OPEN UP
by thotneeshia September 25, 2018
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1) A quote telling you the FBI are here

2) A meme. THE END
Me: Downloads Movies
FBI: FBI OPEN UP
by NintendoNerd December 19, 2018
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When people online are being creepy, the people will comment/reply and say “FBI open up!” showing that if they used that behavior IRL they would probably get arrested.
‘I’m 40 and I like 14 year olds.’
‘FBI OPEN UP!!’
by Tom Holland’s Girlfriend January 28, 2019
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