Ours does this honking and sucking in when she has pulled too hard on her leash. We always use a harness for walks. However, she has also done it just for no reason. It is not often, and our vet said she would need to hear it first since she wasn't sure if it was reverse sneezing. When it is over, she seems just fine. We still don't know what it is, and she is six years old.
