Neighborhood friend of my 6yr old daughter showed her pornographic images. How do I handle this?

My 6yr old daughter has a friend.....we will call her, "L". The night before last, my daughter and L were playing upstairs in our home. My wife was outside the room on the other side of the wall doing something on the computer. She heard my daughter go, "ewwwwww!" and asked through the wall if everything was OK. There was silence, so she got up, walked a few steps, and opened the door. She could see something was up, but L got up and said she needed to go and my wife told her she would walk her back down to her house a few blocks away. My daughter came downstairs and hung out with me and didn't mention it. Later, before bed, my wife asked or daughter again about the ewww from earlier. She said, "L showed me a video on her phone that is a girl putting the boy's privates in her mouth" - this is a small nightmare that I'm realizing no parent wants to ever deal with.....but here I am. The moment I heard, I got in the car and drove a few blocks to L's house to talk to her dad. I don't need to punch him in the face. I do need to tell him what happened, that even though it is an error and we all make mistakes - that I do not accept what has happened, and that his daughter is no longer welcome in our home. They were gone for the evening so I left my number. The next day we were with family for a Memorial weekend get together and I missed his call. I tried to call today but there was no answer. From what my daughter told me, L got the phone from her dad because it was old and he doesn't use it, so she wanted it for a toy. Well, as it turns out, I deal with electronics and my daughter is sort of a little savant when it comes to electronic and computer literacy. She took the dud phone from L, found the cable that fits it, and charged L's dad's old phone. So.....how does one handle this situation that we're in?I explained to my daughter that it doesn't even sound like a real thing and they must have been using some kind of weird pretend or make believe like in the movies. She had no clue what she saw, meaning that there is zero sexuality to her because that concept doesn't even exist in her brain. She's 6, as I said. She simply said it was super weird and she thought it was yucky. I think we can get past this, but I'm curious if anyone has ever dealt with this and if there were any responses to how I intend to proceed.Apologies in advance if there are a few words misspelled or auto-corrected, I'm typing on a phone. via /r/Parenting http://ift.tt/2r3uh5S