You’re moving to your girlfriend’s house and she’s helping you unload everything from your car. For obvious reason, you can’t help yourself and just admire the view, as she keeps bending over and showing you her amazing ass.
This clearly annoys her, as she feels you’re not helping at all, but only for a moment, before she realizes why you cannot move much at the moment. And she knows exactly how to help – after all, the best cure for a raging boner is a great fucking.