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Taking a "massive" dump and not flushing it. Massive Dump, No Flush
I took a MDNF in the CEO’s private bathroom.
by Nathan November 09, 2004
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2
the hipster way to say "my dick needs fucking"

often thrown into random conversations
"hey joe whats up"
"MDNF!!!"
"WTF does that mean?!?!"
"oh; you know ;"
by Simpy April 26, 2009
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