I think it would be quite arousing if my girlfriend(who I am deeply in love with) and I found a neutral third party to film us having sex in a natural environment. It would be an extra turn on to see them aroused as well, whether it be another couple or an individual. The thing is, I don't want to fuck things up between us, so, what is the general experience in regards to this type of...well, thing?

Not knowing you or her, I believe this is a little like Project ORION.

ORION was an idea for launching spacecraft by setting off small nukes under it.

You'll either end up soaring like a god or glowing in the dark.

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Calm, quiet, smooth, devastating

I've been sore. Sometimes it felt like it would glow at night!!!!!

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I like; a) taint brushing: b) a good cigar: c) our juices together; d) champagne: e) protein squirts; f)more of these; g)much more of these; h) Damn, slide that thing into me. Deep!
Adage: 2 things are certain in life; Death & Taxes. Therefore; God & Beelzebub had a meeting to fix the problem. A mighty storm prevailed for ages until finally they ended the storm with the agreement: From now on Anyone whom chooses doesn't have to die. "Everyone wins said Beelzebub. You get an eternally grateful bunch of worshippers praying forever for lower taxes as I goad & prod them forever with higher & higher taxation."

Did it many years ago. She ended up giving him a blowjob, which was also erotic in it's own right.

It needs to be someone you are comfortable with, and you need to not have performance anxiety. (Women have a much easier time in that regard)