How do I teach my stepdaughter how to recognize emotional manipulation without manipulating her myself?

Hey Folks.. first off, thank you for the years of sage wisdom. I have three step kids, the eldest is my daughter, Erica, who is 10 years. Erica is the only child that has any memories of living with her BD and as a result carries an enormous amount of guilt and longing for a lost life with him. She does see him every other weekend but naturally she longs for more interaction to the point she cries at night if he misses a weekend, or doesn't call her after saying he will.My concern in general is that her BD is a very manipulative person and often tries to use Erica's feelings as leverage and seems to feed into them as much as possible. He plays the victim for all of his hardships, blames me and his mother for their separation and has been quite vocal about it to the children which is incredibly unfortunate. BD believes we are the worst sort of people and makes little effort to hid his opinion of us to the children.When Erica was 7 he bought her an iphone for Christmas, demanding we get her online so she can message and call him anytime she wanted to. This was done without consultation with Mom or myself, who limit the children's exposure to the internet. I've been online. I know whats out there. We declined granting Erica internet access as we felt she was to young to be online unsupervised, and to be honest, we did not want BD being able to reach out and manipulate Erica at his will. To be clear we have never restricted contact between Erica and her BD, he has always been able to call her, or Erica call him. Here is the issue at hand.As Erica is entering Grade 6 next year, she has campaigned hard for a phone. She will be busing to school across town and cites that she needs a phone for emergencies, and that phones are commonplace among her peer group. I'm actually quite proud of the arguments she has made, but I digress. Erica also cited that she would like a phone in order to be able to communicate with her BD more regularly, to be able to imessage and facetime with him. This in turn opens the gateway for positive interactions with her father, but at the same time, opens the door for manipulation. So I am faced with this unavoidable evolution in her social life and I want to prepare her for it.How do I teach my daughter how to recognize emotional manipulation without manipulating her myself by forcing my world view, or projecting my concerns about her father onto her?What do I do here? I try to teach critical thinking, evidence vs rumor, the scientific method, but I don't know how to prepare her for the social puppetry that is emotional manipulation. Please, help or advice if you have any to offer. via /r/Parenting http://ift.tt/2rle7TO