Gear - Sleepsack

I really hope I get to try a sleepsack one day soon.  Although I've been mummified with cling film (which I guess gives the same sensation) I've found it difficult to cope with.  A leather or rubber sleepsack fills me with a bit more optimism that I could cope with it for a longer period of time.  I like the idea of being stuffed into one, gagged/blindfolded/hooded, strapped down and not being able to move a muscle...