For the past couple of weeks or so, I've noticed my dog doing some strange things, he seems to suck on his drool (if that's even what he is doing), he then drools an awful lot, kind of like a teething baby and his lip quivers, I've never had a dog who has done this. But he is a four year old English Springer so I don't know if it is something I should be worried about or if it's just an odd habit of his or his breed??