Park sells a self-stick boot specifically for that purpose. However, I used one once upon a time and discovered, even with the self-stick, they do not stay in place indefinitely. So it's the kind of thing you do when you're out on a ride and have a problem- you hope it will keep you from being stranded. But not the kind of thing you do to "fix" your tire.

A piece of an old tire should make a good boot, for that matter.