kos khun

Originating from the Farsi language, Kos Khun literally translates to Pussy Blood.
In Persian slang, it really means period.
Commonly used to describe people that are in a bad mood.

Student 1: "Dude I'm sick & tired of Miss Hand & her shit, she's mad annoying.."

Student 2: "Probably on her Kos Khun."