My sister asked if she could have my car for a week to go on holidays with a friend. She knew I wouldn't need it. I would have my girlfriend's car because she went on vacations with her parents for two weeks. I said yes but I told her it wasn't for free, at first my sister was convinced it was just like the other times, a blowjob or a quick fuck, but no, this time the car would be gone for a whole week so the price had to be higher.