I haven’t done it lately, but I have in the mountains, and Arizona desert, California, national park, and sundry other places. Quite a thrill!
Only masturbate? Hell with that. My spouse and I fucked on top of several mountains when we lived out west. It was a fetish of ours to climb a mountain and fuck on top.
My last house had a covered patio. Big white fence between my house and my neighbor. Their rear driveway ran alongside my fence, and they'd get drunk every weekend. Crossdressed and sucking off my crossdresser friend mere feet away from those fools. Another time, a new friend of mine was a bit overwhelmed when he came and wasn't exactly quiet. I thought for sure they heard, but I guess not. I don't know how many blowjobs I gave back there, but it was a lot.