I actually hadn't seen that quote until after I finished replying and then visited your profile to friend request and read more of what you share there. It was quite enjoyable reading that as it was this!
I'll be the first to admit I have no practical experience in this subject where you have lived for quite a while already. But I enjoy reading and learning of the experiences of others and engaging with a few on a fantasy side of it in a small way ... nobody permanent yet or ever :)
Were you naked in the stall while playing? Maybe the next step will be to fully disrobe and allow yourself to fall into that place where you cant help but touch yourself. There would be no chance of hiding it should one of the women entering see you then ;)