put a condom over the pc's mouse. do this on a regular basis. It will drive him fuckin nuts thinking what the fuck it means. N it doesnt mean anything. Its a condom. They free from family planning. Then start putting them on other things he uses. Trust me it will fuck him off no end. Its just bizarre. And dont ever get caught.ever. It will take u ages trying explain why u been doin it and what the point of it was. There is no point. Its just a headfuck.