Microfoam tape is not the most sticky thing out there, but it sure is the best thing I've ever tried. It conforms to every curve perfectly, stays in place because it's very stretchy, and doesn't hurt at all to remove, not even on the hair. Stuff the mouth, wrap a couple of rounds of this stuff around the head, and see if you can get it off without the use of your hands

I sure as hell never managed to. As much as I love the ruggedness and simplicity of good old duct tape, or even electrical tape (my second favorite), this is just something I would prefer about 90% of the time.