Gotta go to the bathroom

Soon after the start of the lesson you head for the bathroom, as you enter a stall you head clapping noises from the stall next to your, usually you would be disgusted, but this time you are aroused by it. You drop your pants and take a piss, as you clean yourself you notice that your sticky juices have left a huge wet patch in your panties, you try to clean them up, but ultimately you choose to simply go without. You tell yourself that it's cleaner that way, but in reality you simply think that the rough texture of the jeans will feel good on your engorged clit.

At first you put your panties in a pocket, but then you choose to be a little more adventurous and you leave them hanged on the hook on the door. You are about to leave the bathroom, but the situation has aroused you quite a bit, a little teasing won't hurt anyone right? You lean back on the toilet and start stroking yourself: a hand circling around your clit and one pinching your nipple. As if to encourage you the girl in the next stall starts moaning louder, you respond by pushing two fingers in your awaiting pussy. You close your eyes and imagine being in the other stall, with a real cock ramming in and out of you, "Faster", your fingers scrape against your G-spot sending jolts of pleasure up your spine, "Deeper", you move the second hand from your nipple to your clit as you feel an orgasm mounting, the other girl is now begging "Fill me up daddy" or is it your imagination? You hungrily push your fingers in and out another couple of times before feeling pressure mounting inside you, you don't have the strength to react as you release a powerful squirt, your mind goes blank for a couple of seconds.

As you exit the stall you leave on the door your panties and a stain of squirt, outside you find the couple that was banging next to you, seeing them you blush, the girl slides you a piece of paper with her number on it "If next time you want company, we are open to a threesome". You normally would have died of shame, instead you just reply "I'll think about it".