Suckin' dick, makin' money. Used to celebrate, commiserate, show apathy, etc.
Dick: How was your day man?
Tom: Oh, you know. SDMM
I got hired! SDMM!
Mom: you know what they say about kids who don't do well in school.
Mom: that's right.
When two friends simultaneously ejaculate at a shared target.
Thomas and Doug made a wicked chumshot compilation video last Saturday night.
Ed and I chumshotted the neighbor's Sunday paper for revenge after he shit on our yard.