Have you seen anyone with a mouth guard under a full mask? in General Discussion Posted August 12, 2014 · Report reply Uh, no, can't say that I've seen that. In any event, if the masks actually do have too large holes, they shouldn't be renting them out. Check beforehand, just grab a bb and see how hard it is to force it through one of said holes. If they are too large, a second mask is likely to screw with how the first is worn, I would just use a cloth wrap instead.