you play it like at a party or something, cause you need a lot of people for it to be fun. its kinda hard to explain, but i'll do the best i can.
you get a circle of people, boys and girls, and the girls are given letters and the boys are given numbers. then one person is randomly picked to be put in the middle. lets say thats a girl. then another girl is supposed to call a boy's number. he is supposed to try to kiss the girl in the middle, before the girl who called his number kisses him. if he gets kissed, he goes in the middle, if he kisses the girl int he middle, the girl who was supposed to kiss the boy goes in the middle, and then another letter and number are picked to do the next round.
its pretty fun.