Have any of you taken training classes? Our 14 month old pup Theo does not know how to socialize with or behave around other dogs: once he sees another dog, he goes crazy --nonstop barking, jumping, and running around in circles. And when the dog passes, he pulls forward as if he is chasing the dog, and so much so that he starts to gag and pant heavily. We have a harness and have used a collar before but he doesn't get that pulling hurts. Just today, he is bleeding in between his paw pads and we don't know if this is related to his out-of-control behavior outdoors. How should we fix this?