Romanian Aquarium
When you stand on your knees looking up, and get your mouth filled with piss, cum, or in some cases, extremely loose diarrhea. Occasionally, a mixture may be used, often including alcohol. After your mouth is completely filled, you put small fish into the liquid, creating an aquarium.
Me and my friends were bored, so we created a Romanian Aquarium. I accidentally managed to swallow it after a while.