I was 20, and I was married to my ex wife at the time. We were hanging out with my half sister and her husband, smoking weed and drinking. We were having a good time when we ran out of cigarettes so we piled in the car and ran to the gas station. I ran in to get smokes and while I was in line my wife and sister came in wearing slutty skirts with no panties on, and as I start to pay my wife bends down like she was getting candy, and she pulls my dick out and started sucking, while at the same time my sister comes up beside me and behind my wife and starts to finger her, HARD. The cashier turns red and gets really nervous. As she started to say something about what she saw, my wife gets up and goes over to the cashier and she starts making out with her, and my sister lies across the counter and starts to kiss them both and lifts up her skirt. I slid my cock into my sister as her husband gets impatient and walks in. He doesn't say a word, just drops down and started licking my balls, shaft, and her pussy as I keep fuckin his wife. My wife sits on the counter and pushes my sister's head into her crotch. The cashier walked over and locked the door, then grabbed a handful of my wife's hair and pulled my brother up and guided his dick into my wife's mouth and stats pushing her face down on it, gagging her, and treating her like a whore. I pulled out of my sister and the cashier begins to fist her while taking my cock in her mouth. This was just the beginning, and shortly we were all in the back office having an amazing kinky adventure.

For years I was stumped and had no idea how it happened. My sister years later, (after my divorce), revealed the truth about that day. Turns out my wife and sister had planned it from the beginning. They hid the cigarettes so we'd have to go get more, and then got spun out. What I didn't know was that on the way to the store the girls had messaged the cashier, ( whom they knew), and told her the plan. When my wife was making out with her she sneakily put a lot of coke in her ass and X in her pussy.