it means talking bullshit in persian (farsi). and is mostly used by the younger teen generation in iran, and is equivalent to a "shut uppp" in english.
goodarz: "bro i swear hannaneh is telling some kos-o-sher to her bestie haniyeh!"
mohsen: "don't worry about it bro she'll come to her senses.
mohsen: "don't worry about it bro she'll come to her senses.
by Ariashahanshah April 7, 2022
Get the Kos-o-shermug. 
Get the Komug. Kose o share or kose share or kos-share is a persian slang which literally means pussy and poem but figuratively means bullshit.
People use it mostly when someone exaggerating something
People use it mostly when someone exaggerating something
by Mayar Tahsil kardeye khiabuni August 26, 2021
Get the Kos o sharemug. by thisistii March 8, 2022
Get the Kosmug. 
by Henry king James February 15, 2023
Get the jo komug.