DefinitionM personal ads, it stands for full time master/mistress-slave relationship.
QUOTE: Addie (Jane Alexander) to Sgt. Speer (Clint Eastwood) in City Heat (1977): ' That's what you are, right? First, last, always, seven days a week, twenty-four hours a day'. In this case Addie feels that Speer is a cop, full time, all the time, which means that he has little time for her.