When a male moves his lower abdomen, lower body in a way that causes his " nuts to lock up", or get tangled internally.
My husband was so busy being an asshole, by waving his legs at me while sitting in a lawn chair, that he maneuvered his "nuts lock up" from the rapid movement of his lower body; later requring surgery to be correcred..LMAO #KARMA
by Ms.Kitten82 January 27, 2018
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hybrid cross between "grow a pair of nuts" and "man up"
Guy 1: "Oh man, I totally wanna bang that chick over there."

Guy 2: "So nut up and do it already!"
by LOVEMESOMEURBAN October 16, 2010
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I'm was so mad, I was nutting up in there!
Why don't you try nutting up and ask her to the dance?
by Melhon96 January 7, 2016
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Dan, Jay and Jeff came out of the corsey and saw some hot girls. Dan and Jay said "hi!!!111oneone" and Jeff said "nut-up!" The girls drove by and flipped us off.
by dFecT June 3, 2004
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(v.) To gird ones loins. Nutting up entails using one's proverbial balls or "nuts". Mainly used on the US west coast, it's the sister (brother?) term to cowboy up.
I better nut up or I'm gonna get my ass kicked in this fight.
by Neilmiser May 15, 2004
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Verb phrase: To involve oneself in a physical altercation, to lose one's cool, or to fly off the handle. A common fixture of urban or "gangsta" vernacular. Recently popularized by a homophobic, black-clad drug-dealing NPC/pedestrian in the controversial PS2 game "Grand Theft Auto: San Andreas."
"Yo, I'm fidd'nduh nut up in a minute!!!"
by Buddy-Rey November 7, 2005
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Either walk your talk and prove your worth or toughness, or keep your pie hole shut and get the hell outta town.
Keep running your mouth...either rise to the occasion and let me thrash your ass when I grab that stack of dimes you call a neck, or refrain from further trash talk. Take your pick!!
by weave March 25, 2003
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