Extra Appendages

My gym has a room outfitted with massage chairs, and I often use it after my "rigorous" workouts. There's a poster on the wall that explains, in Japanese and English, how to behave (no sleeping!) and how to use the chairs (15-minute time limit!). I've never really looked closely at all the rules, but the other day some text caught my eye. At first I thought the vibrations of the chair had shaken my retina loose. Upon closer inspection, though, I realized it said exactly what I thought it said. Apologies for the blurry pic -- I rushed in order not to disturb the people that were "not" sleeping. The English says, "Please put the spare prick in the basket." The original Japanese says something like "Please use the basket for your belongings." How that translates to "spare prick," I have no idea.