One of the varied terms for vomiting. The Lumpy Yawn generally occurs upon waking from a night of hard drinking. Luckily, most foods consumed while "gettin' yer drink on" are soft (hamburgers) or have been generously softened (tacos / nachos) by a cornucopia of beer, and are thusly comfortably ]retched] back up.
Jeremy Clarkson on quitting drinking: "I haven't had a lumpy yawn for a whole week now. Perhaps that's why I'm still fat; I've stopped vomiting"
This is similar to a normal Queef but the subject is on her period when the air is expelled from the vagina.
The "lumpy" side is when the subject expells blood clots as well as the standard bloody mess.
Man 1: Dude, I was banging Amy last night while she was on her period and I'm not even joking she mega queefed and all this lumpy shit came out all over my balls!
Man 2: I'm not sure if I'm really turned on by that or sickened... Sounds like a right lumpy queef though!
Man 1: I haven't washed them if you want to see...