And not just a hood. Inflatable hood with built-in inflatable breath-throug gag and nose tubes! My dream! Have been looking for such design for years. Found at LatexAS

It turned out that the nose tubes (which are quite narrow) can easily be removed and you can breath through the nose holes (which are also quite narrow :-) The gag is big, but comfortable. The breathing tube can be used not just for breathing. Just use your imagination :-P