A more 'advanced' form of postmans knock in which more physical contant is the norm. In this version a girl or boy is chosen to go hide in a cupboard (or bedroom). Another boy or girl is then chosen by chance (e.g. spinning bottle) or selection by others and goes to the place where the other is waiting. What happens then depends on the rules set but can range from a kiss, or a grope and a fumble to full sex.