Hmm not sure I should be commenting on this thread as masturbation has never been my thing since I first tasted a juicy fanny I much prefer intercourse or letting my partner wank/suck me off. But one thing I can confirm is that nudists are all horny. I/we have visited clubs and nudist beaches and the sexual tension in the air is apparent. This especially being so in the company of guys with big cocks/physigue's or really attractive women. Women via male eyes have very many physical attributes such as curves, long legs, great butts, pretty faces and other things that help create sexual tension. For nudists and those that like mixing with other nudists sex is a constant factor in their minds. There is nothing wrong with that it is natural after all.
My wife was never into masturbating in front of my or my masturbating in front of her as just masturbation. However, once in a while if we were having difficulty reaching orgasm, we would lie back and rub ourselves to climax. She rarely masturbated on her own, but I caught her once in bed with a massage oil bottle up her puss rubbing her clit. Surprisingly she wasn't embarrassed and kept rubbing her clit, then pulled the bottle out and told me to fuck her. She was so wet and stretched from her session that I slid right in. She wrapped her legs around mine as we fucked lustfully each coming hard and loudly.
My wife is used to it and honestly enjoys it when I remove my pants before sitting down next to her. She says "OK, something needs some attention"? She help me out fondling my balls, caressing my inner thigh as I grow hard she'll tease the head and stroke it, then I stroke some as she massages my bung hole which is what sends me over the top to blow my load all over my chest and stomach. She then wipes it up with her fingers to place my cum in my mouth as I lick it from her fingers.