On a long distance bus in South East Asia quite a few years ago. These ones were fitted with three rows of two level beds instead of seats. During the journey I found it really hard to sleep as the bed (more like pod) was so short, I got a little bit risky fondling my breasts and decided masturbation was a sure way to tire me out. PLUS, I've always wanted to try doing something like this in public so it was the perfect opportunity. I lay on my back with my leg closet to the isle propped up slightly to help hide my hand going to town on my clit under the blanket. Watching the scenery, listening to some guys chat a bed or two behind me, and having the sun shine on me was amazing! Don't think I got caught ;) but I did overhear some guy point me out specifically to his friend, once I got to my hostel with my travelling buddies. Recognized him as one of the guys from behind me on the bus, so I don't know if they just recognised me or were watching while I played with myself, but either way it was definitely exhilarating!