The act of anal sex with a one-night-stand at his/her parents' house, and then cleaning the fecal matter off of the penis with the finest drapes in the family room.
This is an act that originated somewhere around the bay area in California. Sort of an urban legend but it's rumored a guy nicknamed "Satch" (no, not Joe Satriani) was the brains behind this act; hence "the dirty satch, or satchmo"
You should have been there man, that girl from last night was really turning out to be a bitch; so I hit her family up with The Dirty Satchmo!
The family could not explain the newly appeared stains on their drapes, perhaps they had fallen victims to a "Dirty Satchmo"