In colloquial English, to cuss is to do down or insult, sometimes by proxy, as in 'You cussing my mum now?'
Back in The Eighties the school playgrounds of London rang out with the cries of kids cussing each other; cussing matches were held, and cussing was the talk of the school. The word is still used, but it's not as popular as it once was.
Daphne and Celeste's U.G.L.Y. is a cuss extravaganza, as is the Bloodhound Gang's Why's Everybody Always Pickin' On Me?.