Slutty College Girl

It's fancy dress for the end-of-year party at college and your step-sister has dressed up as a very cheeky and slutty college girl. But dad has told her she's not allowed to leave the house looking like that! She tells you dad's leaving for work in a minute, so she'll go once he's left, but she has a funny feeling you're going to tell him. Is there anything Natalia can do to keep your trap closed?