You don't spray it in their face at all. You tilt their head, so as they're facing downwards (so they don't swallow any); then pour a small amount into their mouth. This irritates their mouth and throat, and causes them to let go. It irritates their throat on about the same level it does ours. It burns and tingles slightly...
Whiskey, Vodka, Rum, etc. They all work. This would be something to keep by. Even if you never use it....safety first.