Having your salad tossed means having your asshole eaten out with syrup or jelly; syrup is generally preferred. This is usually done as initiation for someone that wants to score some drugs in jail, or by sexually depraved people.
-"Have you seen the new boy in cell block D? I'ma make him my bitch; he'll be tossing salads by the end of the week!"
-"Mary is a freak in bed; last night she tossed my salad!"