pushing flannel Share definition Flag When you have to take a shit so bad that it's popping out of your asshole and pushing into your flannel underpants. I drank to much free coffee during that training session and now I'm seriously pushing flannel. pushing flannel by pushinit12345 April 1, 2007 0 0 Get merch Get the pushing flannel mug. Buy Now — $32.95 See more merch