Kind of like farting in the bath and producing the bubbles, but in the shower. Basically if you need a fart in the shower, have your back facing the shower, cup your hand over your ass crack and let water dribble into it. Let the fart rip, enjoy the sensation of a hand contained bubble.
Grandpa - "enjoy the puddle farts while you still can boy, last time i tried it grandmaspent the week cleaning up shit from the shower."
while having anal sex with your partner, you proceed to urinate inside his/her butthole. Followed by removal of the penis and lying on the ground (preferably a solid and easy to clean surface) your partner still containing the urine inside them proceeds to deficate on your face.
"oh my jenny, whats that awful stain on your new carpet?"
"Oh thats just last nights mississippi mud puddle, we got a littlewasted"