'Stop Talking To Me'
Usually used when you want someone to know you don't like them, or you're just having a bad day. Either way, sttm.
Friend: bro, me and the boys got so done last night
Friend: wanna hear what happened it was sick?
Me: no sttm man
when someone is chatting shit, and not telling the truth
Person 1: *says something obviously not true*
Person 2: "oi nah just stop galvanizing"