When you completely break down or lose control. Can be used positively or negatively.
"He tripped and fell into the pool and I totally lost my shit; I couldn't stop laughing."

"He tried to shove me and I lost my shit; I beat the hell out of him."
by WTFuchs November 30, 2011
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When one cannot keep control of oneself.
Prematurely Ejaculating
I tried to hold on, but I totally lost my shit!
by kneecapper December 19, 2006
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(n) (1) to lose ones shit is to see something or hear something funny or scary, and to laugh or be scard so much you defecate your self.

(aj) (2) i lost my shit can also be a figure of speech to explain something funny or scary.
"did u see that guy get hit in the balls? "

"yer i lost my shit lol"

'i lost my shit that was the scariest girl is have ever seen"
by jaydos123456 January 17, 2011
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