A crowd of men

As you and Mia approach the bathroom, you start to hear a loud cheering coming from a crowd of men. You arrive to find a sizeable crowd gathered around the final bathroom stall and whatever Mia thought she understood about the situation clearly vanishes as she only becomes more confused. You drag her closer to the crowd and start to hear Tracy moaning from within the stall. Realisation dawns on Mia's face and she looks through gaps in the crowd with a face of shock and horror. She can't make out much through the pack of men, but what she can put together is Tracy being fucked doggystyle over the toilet by some guy.

"Oh my god, I can't believe this, is that really her?"

Mia looks to you for confirmation of what she believes to be true. You simply nod, which causes Mia to look on in stunned silence at her twin sister being pounded from behind in the bathroom stall, whilst a crowd of horny men look on, awaiting their turn. As the two of you look on and listen to Tracy having her ass cheeks clapped, you notice Mia biting her lip as she watches. Could she possibly be getting turned on by this? It would make sense for her and her sister to be into the same things, and you knew Tracy biting her lip was usually a sign that she was getting aroused. You decide to put this theory to the test and wrap your arm around her waist. When she does nothing to protest, you move your hand further down and grab at her ass. At this, Mia snaps out of whatever trance she's in and turns to face you.

"Wanna get out of here?"