No aggression, me and Autumn play like this all the time and she isn't the least bit aggressive. She doesn't bark as much but some dogs are loud and some growl when the play. I think when you are laughing it helps the dogs to realize you are playing too. It builds trust when they can play like this and know you are going to hurt them. Dogs can trust you more when they can predict your behavior so I think if you stopped playing like this she would think something is wrong.