Slip lease use and how to manage bites bites coming out from enthusiasm.

I have an 11 months old female dog (22 kg dog) and since I have her (2 months old) she likes to bite. Mostly for playing, in relief of her teeth later and this has slowly became a habit to express and releif herself when she is enthousiastic about something or when she doesn't want something to happen. The bit is not like attacking aggressively, is like requesting what she wants but is combined with her voice sometimes. For example, she loves playing and when she demands attention she starts running, taking her toys, calling to play with her and while this builds up, she then might start bitting shoes, ankles, or whatever is closer to her. She cannot manage not winning what she wants. The tention of the bite is building up. The first is not that hard and in a more playful mode but then, is getting more intense. So, this is the first behaviour around biting. The other occation is when something that she doesn't like is happening. Simple as, I want to go on the right during our walk and she wants to go to the left". Then she might lay down or pull to support her opinion and if I insist by pulling her, she then would come after my legs.

So I started going to a new trainer who told me that the dog doesn't know how to communicate with the lease. And he did a training session with her to teach her how the slip lease works by reassuring me that she does not hurt and the tention that the she gets on her neck is less that what she used to have with the simple coller while beeing pulled. He then tought me how to "drive" her with this lease. Walk, turns and stop.

First of all, I am not very comfortable with this lease and an not convinced that is not abussive. I would much like your thought on that. Is there any way to make it worse?

And second, is this a behaviour that you have experienced in the past or is this a nice tool to work on this problem?