When you have built up gas that you've been trying to hold in, and something makes you laugh. This results in a vicious cycle of losing control of your bowel and anal muscles and farting up a storm from the impact of the laughter, then laughing more at the farts, causing more farts, which causes more laughs, which causes more farts, and more laughs, and more farts until there is no gas left inside of you.
Farts usually expel in rhythmic timing according to the laughs. It's like unintentionally playing an instrument.
The Laughing Farts:
Yesterday at school I was holding in a fart, and my friend passed me a note that made me giggle, and I lost control for a second and blew a huge one. So then I started laughing even more and I farted even more and I had to run to the bathroom laughing and farting and the whole school was watching me. Traumatizing.
When a girl teases the other partner/s with her vaginal fluid (Rubbing it around, licking it, etc) as a show of thanks to pleasuring her. Appreciation/Percolation!
Before we got really down and dirty I let her lick my abs. And then she rubbed her vagina juice on them as a sign of appercolation!