Was on the subway platform. Three adorable French girls (early 20’s) chatting near me. I offer to take a picture for them together. I snap three or four, then walk ten feet away and jerk off leaning against a column by pressing my fingers against the thin fabric of my skirt. My back is visible to them, my front is facing the tracks. I was caught by the intensity of the orgasm and would have been outed except that the train pulled up at just the right moment to drown out my yelps.