The act of using human feces for lubrication for vaginal sex.
Bob: So, did you get some ass last night?
Tom: Oh God yeah, the chick even let me brownie tunnel her!
Bob: Holy shit! Nice dude!

Sam: So do ya think we have time for some brownie tunneling?
prostitute: well.. If you insist. Make sure you pull out though..
by Noah Hizzle May 2, 2008
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