idiom: a ritual carried out to inform a guest that his presence is no longer welcome. conducted in stealth, by taking a prized cactus of said guest and chucking it amongst last night's fish bones and vegetable clippings.
It is customary for dinner guests to each bring their own cactus to a party, and at an opportune moment the offending party's cactus will be pitched into the garbage. The fruit may be thrown away unharmed, or violated in any number of ways beforehand.
Also called: "Pitching the Cactus", "Chucking the Cactus", and "Wasting the Spiny Fruit".
If that knob keeps hanging all over my girlfriend I'm going to toss the cactus and send him crying into the street.