I Pissed On Floor
It was my last week of school and on the train back home there was essentially no one (at least in my wagon) because my school finishes later than others. I checked where the personel was and I took the chance: I lowered my pants (enough to pee, but not enough to be caught), sitted on the eadge of the seat (I would have liked to wet the seat, but it was of leather...) and pissed on the floor for a few seconds. It was so naughty and amazing! I stopped the flow, fixed my pants and then I went next to the doors waiting for my stop. That was the only time I was completly alone and had the chance.