Cosplay Turned My Sweet Stepsis Into a Total Cock Fiend!

My stepsister wanted to go to a comic convention dressed like a slut! I knew her outfit was a cosplay, and she looked hot, but our parents put me in charge while they were away, so I was not going to let her go out looking like that. Everyone would be picturing her naked, just like I was doing! All it took for me to change my mind was for her to suck my cock dry while wearing her slutty costume. I was hesitant at first, but her wet lips felt so good around my hard dick that it was worth it. Luckily for me, the convention lasted for multiple days, and every costume was tighter, smaller, and more revealing than the last. Since the first time I wanted to touch her ass, the second time I asked for her big, beautiful tits, but her third cosplay was lingerie! Only some underwear, animal ears, and a buttplug with a tail! If she wanted to wear that outside, she would have to do more for me. That time, I wanted to pound her tight pussy and fuck her right in her perky ass until my cum was inside her.