The easiest way is to simply play a correspondence ("online" in Erikspeak) game that is unrated and with takeback moves. There is another option designed for teaching that I've never had to figure out but I'll try to find a link to it. Here you go; looks both powerful and complicated so good luck with it.
http://support.chess.com/Knowledgebase/Article/View/160/19/how-do-i-use-the-live-analysis-board
Is there a way to invite a specific user real time to a non comptetivie, teaching/analyzing board to just go over moves? Something without a timer or rating. Thanks in advance!
Ivan