Is this what we want to know about Keith? Really?
I'm about to disappoint you. I don't get off on touching myself in weird locales or situations. Masturbation for me is like maintenance work. I do it once a day to keep the pipes from a'cloggin'.
The weirdest place I've ever masturbated is tame, but it does come with a story.
I was a late-term masturbater, and the first time I ever wrangled myself to completion it was a mistake. I was in a situation where people were getting naked. I was young and embarrassed that my penis size wouldn't be up to snuff. (I'm on the very upper end of the grower/shower spectrum. I grow so much, in fact, that watching me getting erections is like getting a surprise, 3D screening of The Howling.)
I ducked into one of those city parks, a place with a bench and a little creek and some trees, fabricated to break-up the monotony of all things, and did what I knew would work. If I touched myself some, my penis would get bigger. My semi is a whole lot more impressive than my typical resting state, so this was a good plan. Only, I was in a hurry.
You get the rest. Needless to say, I didn't end up showing my once again flaccid penis to anyone that night.
Short Answer: Bonus Top Ten: Things Girls Have Actually Said to Me Upon Seeing My Disproportionate Erection-Ratio-Situation
9) "This could be an issue."
8) "It's like a muppet."
7) "How do you live with those things?"
6) "Fucking hello!"
5) "Holy shit. I was worried for a second. Did that hurt?"
4) "(laughing) That's...that's a monster, dude."
3) "Where did that come from?"
2) "You just went from bunny slope to black diamond."
1) "Huh. Melissa was right."