my boston rolls apon his bones toys and "bites" them. this happens when he's very happy. he pulls the funniest face when he does. makes growling noises. he doesn't bite what he's not allowd to but he does grab his toys. when i play with him he'll bark and jump. this is not agressive with him. with your dog i cvannot give an answer. i'd need to see the dog. but why do you take him off the couch when he does this? when does he do it? if you leave the room instead of removeing him from the couch what does he do then? the dielating pupils means excitement eand not neccesarily argession.