How to set up a friendly game with take backs?

I realize this is a dumb question, but I can't figure this one out. I want to play a friendly game with my nephew where we can take back moves. How can I do that?

Also, we don't want the games to count towards our rating or anything.

Thanks!

There are no takebacks here, so it is not possible on chess.com.

As for the unrated game, when you create a game, there is a certain slider where you can choose the game to be unrated.

Alright, what about some sort of "analysis mode," where either side can move all the pieces (white and black)? That's really what we need. The classroom setting (under Learn -> Classroom) seems to let only one side (the "coach" side) move. 

There is another site that has everything you are looking for.

Thanks for the hint. I believe that serious games should not allow takebacks and stuff like that. But sometimes I just want to play with my little nephew and not make him feel bad every time he hangs a piece. I also want to be able to analyze a game and let him try different lines.

https://support.chess.com/article/590-can-i-take-back-a-bad-move