[MFN]

I wasn't involved, but my wife told me about fucking outdoors during a thunderstorm:

Before we met she was on a backpacking trip with her college outing club, and after several days on the trail one fellow who'd been hiking behind her and staring at her ass for days couldn't put it off any longer and told her he just had to fuck her. She agreed, so that night they snuck out of their respective tents and met on a flat rock a short distance away, and, naked in the dark, began fucking. Soon a summer heat storm came up, just lightning flashes but no rain. In telling me this story, my wife said it was exciting to be having orgasms in the open air under the night sky with thunder and lightning all around, but she learned at breakfast the next morning that the thunder had brought the other campers out to watch the lightning, which of course was illuminating the scene every few seconds. She learned that the others sat hidden close by and watched her fuck for more than half an hour before returning to their tents, from only a few meters away. During the remaining days of the hike they tried repeatedly to embarrass her about seeing her naked and watching her fuck but she deftly turned it into humour, saying it was like having sex under a strobe light, although her partner was very embarrassed.