Obsessive barking! Help needed!

[Nagini]

Hi everyone!

I have a 15 month old female presa canario, Lily. We have worked alot on her and she is overall very well behaving and obedient dog. She has had many awakening problems in the past but we have worked on them hard and she has overcome them.

Now I have a problem and I have NO IDEA how to approach it!

This problem started when I took her abroad to visit my family, the whole trip was pretty stressful for her (I think), everything was new. I took her to the dog park there after few days. There was two dogs, they played very nicely together, and they left Lily out of the play. So Lily was "the third wheel". The others didnt include her in the play and Lily started barking. She has always made a little sound when she plays, I don't mind that, but I would not allow barking at all.

She goes to a position where her butt is up and her front body is down on the ground, the "play-position" and she lets a loud bark. Runs around a little, barks more.

She has done that now for the third time (third time we are out playing with dogs), and I came home with her.

My first reaction would be to get to Lily, make her stop, pull her on the collar just quickly as a correction and say "Aa-aa!" (thats the sound we make when she does something wrong, and she knows that sound). But the problem is in order for me to correct her as I would like to, I have to catch her exactly at the right nano second when she barks, and catching her is not that easy when she is running around and playing with dogs!

She is taught to come on command, but I do not want to tell her to come and then tell her off! That is abusing the command.

What I think has something to do with this barking thing is that she is pretty dominant by nature, with us she is perfect, when she goes play with other dogs she migth be too dominant (?) for other dogs and they refuse to play with her?

How should I look at this and what should I do?
She doesn't hurt any dogs, or humans, but I want to stop something I dont like, and I want to stop it right away!

Thanks for all the help!

Im gonna add a picture of my princess here so you get to see her :-)