There is nothing better than actual experience versus research for one's novels. As you know, many of my stories have BDSM in them and I scrupulously research them via reading or attending workshops or practising on myself. But I had never been restrained until recently (it's not quite the same thing to tie yourself up with one hand!). I had always wondered if I would panic, since I do get claustrophic, but when I tried it out with a friend recently (even going as far as being blindfold as well) I was suprised to find I did not panic at all.
At least, not until my nose started itching and I was very aware that I couldn't move my hands to itch it. Some rapid nose twitching didn't relieve it but the friend did the honours when requested.
It made me chuckle when I thought back to all the erotic romances I've read and I can honestly say I have never read any incident when the heroine (well, the female is usually the person to be tied up unless it is a gay story) has had any sort of itch on any part of her body that requires her to move her hands (or any other part of her), nor a cramp, or dust in her eye, or hair irritating her face, or material/clothing tickling, or any of the thousand and one reasons we move! I'll have to add something in now, just for realism!