sadistic fucker arent you....ha.....nah but they way i do it is hypreventalate on the floor for like a minute then, just before you stand, have a mate cream a bong, then you breathe out stand up and empty the chamber (NB your first full breathe is the bong) get it right and you mate will have to catch you... then you come round within like 30s and your fucked...haha doesnt work if your all so fucked....you jus wake up a while later with a sore head