Reminds me of that asshole dog Jack. He pulls this shit on me all the time, usually when I'm physically trying to move him out of my way or from a spot he shouldn't be in, like my fucking bed.
I know he's all bluff though because when he's doing it I can grab him by his cheeks and plant a big ol' kiss right on his snout and his reaction is quit growling for a second and try to shake hands with me.