I've seen dragons do that before, but sorry, not sure what it means, if anything. What has she been eating? Could anything be stuck in
her throat (it seems like a "deep breath" to me), I'd try encouraging her to drink water (drips maybe?) or see if she'll eat a favorite item?
If she continues to do this, I'd call a vet & ask about it, maybe get her checked out. (She reminds me of someone trying to burp...?)