When I was younger a group of us (mixed boys and girls) were playing poker at one of my mates house. My younger sister (1 year younger) was friends with his sister to so they were in the other room. Well with poker and drinks it got to dares and nakedness. One dare was for one of the lads to go and get a pair of my mates' sisters panties and put them on his head, but being stupid he went in the room and asked her. They said only if they could come in and watch us make fools of ourselves. Long story short they ended up joining the bet game later in the evening and I lost and had to become my sister and mates sisters slave.