Don't look for this precise scene in an episode of the TV show Supernatural (CW). It never happened. Well, it could have, but it was never shown on screen.
I've always wanted to draw a fan art of the Winchester family pre-Supernatural when the father John, was hitting the road with his two kids Sam & Dean, "hunting things" and trying to train the boys in order to turn them into Class-A ghost hunters.
I came down with several ideas including the whole family in their mythical car, a big and fantastic 1967 Chevy Impala but I finally focused on the relationship between the two brothers and how the elder, Dean, started to get obsessed with his mission of protection his little brother.
You can find a short tutorial here at my Live Journal if you are interested : http://petite-madame.livejournal.com/1698.html