Your girlfriends sister Sophia is on the floor clearing away all of her clothes, she is wearing a very tight top with no bra and its slipping down her nipple. You decide not to say anything so you can get a good look, you can feel yourself getting hard and Sophia is beginning to notice that you seem to be paying her more attention than usual! Sophia spots the nip slip and at the same time sees the bulge in your trousers, luckily she has always been the more fun sister and she is definitely up for some naughty fun with you.
