Dirty Brajan is a disease which is highly contagious and effects the asshole usually after anal sex.
Symptoms include: Dry and itchy anus
Karen: do you want to go out shopping?
Susan: can't, I have the Dirty Brajan.
Karen: ah yes, I feel your pain.
A dirty brajan is when you want to do the dirty while listening to Billie Eilish and licking yourself like a cat.
Some one: want to Netflix & Chill?
You: No, how about the Dirty Brajan ;)