I had been in town with my slave but it had been a work do so we were masquerading as boyfriend and girlfriend. We were both dressed smartly and had been on our best behaviour. My slave had wanted to go to the loo before we left the function but I had told her that she was now my slave again and that she could not go. We walked to the Luas and waited for it to arrive, While we were waiting, the slave asked to go to a nearby pub to use the bathroom but I again refused her permission. We got on the tram and headed out to West Dublin. The slavve was getting increasingly antsy and whispering that she wanted to go pee. I pulled her in close and put my hand over her crotch to feel the desperation and once again refused permission. It took about another 30 minutes to get to our stop but we didn't get off. Instead we carried on another couple of stops to a Park & Ride stop which would be fairly empty at that time of night. By this point the slave is desperate and almost in tears from holding it in. We got off at the stop and I held her on the platform. After the tram had pulled away I raised her dress, pulled down her panties and we squatted together, my hand over her cunt. I told her she could piss and she let loose a torrent over my hand and onto the floor. This bit is all true but I always fantasise that on the opposite platform was a single female who was watching us. After the slave had finished peeing, we stood up and I take my wet hand and the slave licks off the wetness. I put my hand back down to her cunt and masturbate her while the woman looks on. The slave is begging me to finish her off and is calling me master loud enough so the woman opposite can hear and be quite clear of her submission to me. Once she comes, I support her until she is steady again and I remove her panties, leave them lying in the puddle of piss and we walk off.