When you fuck a girl on her period, and you don't wipe the blood of your dick and fall asleep. The next morning the blood dries up therefore leaving you with a brown dick.
Last night I fucked a girl on the rag, I haven't showered yet so I'm Brown Dicking It!
when a white person puts brown stuff on their face in an effort to look spanish, indian, muslim etc....a less harsh form of black-face
grandma: i think that dude in slumdog millionaire is white
me: huh?
grandma: he's british and there are no british indians!
me: so u saying he brown faced himself??
grandma: i guess so