Yes my morkie puppy (Sake) does the exact same thing!!!! He does that when he gets too excited ot worked up! Or even when we're playing fetch and he is anticipating the toy being thrown!!!! He just starts getting all jittery, with the lower lip quivering....so so adorable!!!! I love it so much I sometimes actually hold on to the toy in the air and wait a bit before I throw it so I could see the lip!!!!
Yes, I torment my dogs like that!!!
