That's never happened to me before

Last night, just as I'd walked across the railway bridge, some man 'indecently exposed' himself to me - he had his penis out and was masturbating, asking if I wanted 'any of this'.

I ignored him (I was on the other side of the road) and called the police when I was around the corner.

Odd location - in no way is it a cruising ground, it's a reasonably busy walking route. My guess is that he had some mental health problem, meaning I was more sad for him than pissed off / scared.