"When the parents are away the children will play." Having the house alone and inviting your girlfriend or fbuddy over and having a sex-stravaganza. Includes: Running around the house naked, taking the dog for a walk, doing laundry, making dinner, sleeping over, and sex everywhere. Can be for hours or days.
Guy: Hey gf my parents are away this weekend wanna play house?
Girl: I love playing house! I'll bring the condoms!