The act of having a mad case of the pre-poop farts. Where the gassy air gathers so heavy in your underpants, as you finally pull them down and sit to BM, your face is in the exact spot your bundle of farts were as you pulled down your pants. Hence no fresh air and resulting in a self dutch oven.
Scott: Phil man that ice cold draft beer last night has loaded me with air.
Phil: Me too. Those wings have done a hellish number in my lower abdomen as well.
Scott: Dittobro I was farting so bad running from my car to the rest stop bathroom, the release was so great I didn't even care I gave myself a massive self dutching.