a sexual act in which one partner is upside (via handstand or being held upside down by another) and projectile diarrheas in the air, like a volcano erupting, while the other partner awaits below to have the diarrhea rain upon them like hot lava
When you open a woman/mans prolapsed asshole and fill it with a flammable substance like gasoline or lighter fluid. You then light the substance on fire and watch the anal cavity explode in a firy plume of shit and possibly semen.