Looking over, Ashley and Sara were right next to us, in the same position, Ashley still playing with Sara’s twins. Ashley looked over at us, her and...I locked eyes for a moment. I grinned and winked at her. Moving perfectly in sync with each other, Ashley and I each moved down a little further on our respective girls, slipped our hands into the sides of their panties, and with one smooth motion slid them completely off. Lauren and Sara were looking at each other too, both fully nude now, they. Days like that I couldn't wait to get home and "change out of my uniform" (a great excuse to ensure nobody walked in on me). Sometimes I didn't even undress, the moment my door was safely closed I'd flop down on my bed, skirt up and undies down, rubbing my clit with all the pent-up lust of a long afternoon fantasising.One rainy afternoon (it's funny the details you remember years later) I must've been feeling especially horny, or maybe class felt especially boring. I asked to be excused to use. But wearing my new tiny black thong with black heels made me feel rather naughty and sexy. The train was already crowded when I stepped on, and it got more crowded, and more cramped, with each station stop. I found myself pushed to the back of the car, holding onto a center pole. As the train rocked back and forth down the tracks, I became aware that my rear end was bumping steadily against someone standing behind me. I didn’t think much about it, until I noticed that I was feeling something. Sandra thought she would faint but she did as she was told "thats a nice ass you have"Lisa said now come over here and lay over my lap " please dont humilliat me any more "Sandra sobbed im going to spank you now Lisa said now get over my knee .Sandrs laid over Lisas knees sobbing her heart out Lisa lifted her hand and bought it down on Sandras ass Sandra scremmed she was crying her eyes out Lisa really spanked her ass Sandra was jumping about all over Lisas knees then Lisa opened Sandras ass up.