Cut The Brown Wire Edit Meaning

1.

To excrete wind, or fart.

In extreme cases, to go for a dump / soil one's self.

Taken from Lethal Weapon:

Murtaugh: "Come on, man, come on!"

Riggs: "I dunno, what one should I cut"

Murtaugh: "I don't know! Cut the brown wire!"

Riggs: "OK, here goes......"

Riggs: *parp*

See fart, dump, soiled, parp, brown