Adrenaline?

I think it has a lot to do with adrenaline. Several experiences lately have shown me that risk is a big part of the equation.
Any time I tie myself up and there is some risk that I won't get myself untied fast enough to avoid getting caught, my heart races, my sinuses and lungs clear up instantly.

I had a cold last week and took a few such chances while staying at my mother-in-law's house. WOW! Those annoying cold symptoms totally disappeared. With the bedroom door slightly open, mother-in-law could get home any moment, and may look in, and I would have to perform some time consuming naked gymnastics to untie myself. Hearing the garage door open was a little piece of panic. Knowing that could happen is what kept the adrenaline up.

Thinking about other situations...
Being naked for the first time in front of a new person, or sharing my interest (in being tied up) with a new person, or anything that incrementally breaks another silly taboo... opens me up to another level of truth, or intimacy. It is Taking a risk.
Getting "caught" by somebody who would be surprised or shocked adds another kind of risk.
Being totally physically vulnerable is adding another risk on top of he intimacy risk.
The slim chance that someone would take advantage of me sexually, or want to toy with me is just as terrifying, but also is the stuff that fantasies are made of.

Adrenaline isn't the whole story. I think it is a big piece, but there is also something cosmic and relaxing and settling about being stretched out naked for extended periods. This is true only at certain times. I can't help but think that it has something to do with radiating chi, communicating spiritually, connecting with other times or planes.