set up the air mattress
When you run upstairs and have lightning fast sex with your boyfriend while the houseguest uses the bathroom.
Houseguest: "where are you guys?"
Boyfriend: "just setting up your air mattress!"
Houseguest: "where are you guys?"
Boyfriend: "just setting up your air mattress!"
Hurry up, let's go set up the air mattress - we only have 4 minutes!