as a wee lad we used 2 do these things called risers where u toke a spliff/bong and sum1 picks u up and squeezes ur chest, u hold ur breath and get a headrush. however, if u get 2 ppl holdin u up and another 2 pushin on ur chest it proper ko’s u and u collapse to the floor unconscious. havnt dun it for ages but it was bludy gud fun, id recommend it 2 any1!