A weird invertebrate insect that reproduces through penis swordfighting. The first worm that is stabbed by it's opponent accepts the other flatworms penis and allows it to inject it with it's cum. This term may be used to describe a faggot who is bad at fencing.
noun: I was in my hot tub masturbating when on the side I saw two flatworms swordfighting.
adjective: Do not adopt that Malaysian orphan because he is a flatworm.
by Abu Nazir December 26, 2014
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Flatworm friday !!!
Originally a video of a sped up flatworm (A tiny and beautiful aquatic animal) swimming with the "Inkopolis News" theme from Splatoon (The first one, on the Wii U) playing in the background.

Note : This gif down here, is the only "Flatworm" gif I could find. Do not ask anything about what they're doing.
Dude 1 : Hey, it's friday !
Dude 2 : No ... It's FLATWORM FRIDAY !!!
Dude 1 & 2 (Shouting, dancing the kazotsky kick and singing "Popipo" by Hatsune Miku) : FLAT-WORM FRI-DAY, FLAT-WORM FRY-DAY !!!
by Magolor_800 May 3, 2023
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