Post Office is a kissing game played by boys and girls at parties.
It has been referred to in popular culture since at least the 1880s.
The group playing is divided into two groups – typically a girl group and a boy group. One group goes into another room, such as a bedroom, which is called "the post office". To play, each person from the other group individually visits "the post office". Once there, they get a kiss from everyone in the room.
They then return to the original room. Once everyone in the first group has taken a turn, the other group begins sending members to the first room.