To control condensation on your bag opening, the best solution I have seen is from Sean Emery (Shug). He made a kind of bib from a piece of fleece, that goes over his head. It is about 2' long and collects the moisture that you breathe out, freezing it to the bib and not your bag. I use a shemagh for the same purpose, plus it is a multi-purpose item.
If I was camping and one of my buddies was using a snorkel to sleep, I would fill it with hot sauce.....or worse. :38:
do you have a link to that?
How could you sleep with a snorkel in your mouth?
PMZ
I've fallen asleep twice while scuba diving... jus sayin.