A back room can be defined as either a sex room or a game room.
When it is a sex room, the partners, or party, partake in "activities" of which genitalia
. This is often referred to as back room sex.
When it is a game room, the user of this room participates in playing various video games. This is often referred to as back room gaming.
Girl: Why are we hanging out in the back room again?
Boy: We're gonna have some fun
Girl: Back room sex?
Solo Boy: Man I love playing Majora's Mask
in my back room!