It means "I gotta Pee" or "I gotta Poop."
but its a good term to use when you don't want to disgust people that picture such things as a turd in a bowl and a stream of yellow(not lemonade).
Person 1: Hey dude, do you hear that? It kinda sounds like... What's that word? Brown Note?
Person 2: BRB!
Person 1: Why? I thought you were done with everything?
Person 2: IGP!!!!!!!!!!!!!!!!! bye
3👍 1👎