To minimize someone by ridicule, mockery or derision, especially if the clueless subject does not realize he or she is the target of ridicule. British in origin and similar to "taking the piss" out of someone.
Dick: (with mock sincerity and theatrical enthusiasm) Dang it, George! You like totally RULE, dude! I can’t decide if you are like, a great president…or like, THE greatest president!
George: (with feigned modesty) Shucks, Dick…t’aint no big thang!
Laura: (to George) CLEARLY, you are as dumb as a box of hammers and I would like to kick you as far as I could kick a lemon meringue pie…as usual…Dick is TAKING THE MICKEY OUT OF YOU!
Tony: ‘Fraid not, Dodo-brain girl! George IS the greatest (and cutest president) EVER! Boys rock!
Laura: (exasperated, to Tony) Shut your festering gangrenous pie hole, you putrid tool
! Crawl back into the Masterpiece Theatere “Veal Crate” you crawled out of, boneless-boy.
George: (to Tony) Yo, Tony!!! Who’s Mickey?