A Downriver Jellyfish refers to the aquatic marvel that is indigenous to the southern portion of the Detroit River. Its composition consist of one used latex condom with ejaculate, knotted off and released into the water. Downriver Jellyfish are often observed floating in marinas, canals and occasionally known to wash up on beaches.
"Hey Steve! It must of been a real fuck-fest last night, there is a school of Downriver Jellyfish floating near the boat".
a dude masturbating in the shower; the semen fallen to the water soaked floor look like little jellyfish swimmin' around.
"I was dropping jellyfish so much last night my bathroom is its own underwater ecosystem."
most obvious when water level is at least an inch, and your face happens to be down close enough to the floor.. also exemplified by liquid soap squirted into a basin of water.