Beginners board

Not sure I can explain this properly, but i'll try:

I'm helping out an unrated player, a complete newcomer to chess. I can't teach him much, but what I can, will give him a leg-up.

I'm talking him though each of his moves, telling him how i'm going to respond, etc. But the trouble is, a couple of times .. if i'd let him .. he would have won! And as happy as I am to show him the ropes - i'm not about to lose heaven knows how many hard-earned rating points for my trouble. 

Now .. I'm sure that somewhere on the site i've seen a games board which can be used (instead of he normal one) precisely for this sort of situation. Far as I recall, it allows players to experiment with their moves, before they actually make them.

Did I dream it, or does such a facility exist?

Thanks

Jo

Play unrated.

Another option is to use the analysis board in (unrated) live chess. It allows you to draw arros, highlight squares, etc.