If you’re a naturalist, exposing your dick to some ultraviolet rays is just part of the au naturale experience (just as long as you apply some sunscreen).
It is referred to as “sun-cock,” or rather “sun-cocking.” Basically, it’s a belief that the secret to greater potency is to let his dick soak in some rays to boost his overall, let’s just say, morale.
Naturally, I Googled this astounding member of the male sex’s resolute faith in sun-cockery, and I’m ashamed to say I wasn’t surprised to find some fellow believers.
Early ancestors walked outside naked in the sun, looking back at ancient statues these guys all had massive penis’s, everyone wears clothes these days so they’re not getting the sun on their dink.
The sun’s rays to the penis could make it grow to maximum potential during puberty. Like a plant growing in the dark compared to a plant growing in the hot sun.