Thanks for the comments and questions.
I wasn't held prisoner for too long...around three hours including the rubber sleepsack.
The rubber sleepsack was incredibly restrictive because it was small and tight and also because of the straps that were fastened around me. However, the mummification was also very restrictive because there were multiple layers. Underneath layers of duct tape there were also several layers of black pallet wrap. The head mummification was particularly challenging as I was only allowed a small nose hole to breathe. I came very close to having a panic attack at one point but was calmed down by the guy who was keeping me prisoner.
By the time I was placed in the sleepsack I was really ready to come out. Unfortunately, this didn't happen and the rubber hood/inflatable gag combo was used to keep me silent and still as can be seen in the last part of the video.
The guy who mummified me is the manager of a bondage club in London who I have come to know online. He was visiting nearby and offered me the opportunity to be mummified for the first time.
Since this video was recorded, I have been pallet wrapped twice as part of an overall bondage/captivity scene. Videos for these scenes can be found at https://vimeo.com/189422061
Be warned, the (non-sexual) bondage in these scenes may be a little strong for some people's taste.
Comments always appreciated.