It is more sad and desperate than erotic, but since you ask:
I used to travel a lot, away from home and alone: meeting and dealing with new people without staying long enough to really make friends, often worn out and exhausted and wanting only to go home or at least have some more constant real close companionship.
I was in a hotel, on my own, far from home and lonely.
I was also intensely horny, in that way when sex presents itself as a shortcut to the simple close human contact one really craves, when you fool yourself that the purely physical can stand in for the emotional that is what you really miss.
I am no stranger to masturbation in such circumstances, but that time I needed more: I needed at least the illusion of not being alone.
I kept the drapes open, the lights on, and masturbated, naked, on the bed, hoping men might see from across the courtyard.
Then I imagined them working out where my room was, coming there, finding the door open (it wasn't..), sneaking in, standing in a guilty silent group, watching...
Nobody did, but I orgasmed very hard from thinking they might.