I've been diving for a few years now, I've got two masks - my main is a Mares Liquid Skin, my backup (which I haven't had the need to deploy as of yet, outside of training, but better to have and not need rather than need and not have) is a Scubapro Synergy II Twin. I do not wear a beard, and I make a point of shaving before diving. However, with both of them, I have the same problem - when I twist my head around, they don't so much as leak as they flood, filling with water within a few seconds. Doesn't happen all the time, but often enough to be a major annoyance. Given that my main underwater pursuit is photography, which leads to some major contortionism, this is less than optimal - for example, shooting directly upwards while very close to a wall is a particular challenge. Is this supposed to happen, or am I doing something wrong? I don't know if this is relevant, but I have very little in the way of hair (weekly pass with clippers, no guard) and I don't use a mask strap cover.