Had a big break-through on number formation with DS last year, by joking about the process and laughing at mis-writes. Humor is a great tool for dispelling anxiety and negative thoughts. Also, some theories out there suggest that it helps reduce encoding wrong processes. Along those lines, I would also be careful about how you present things: redoing something because it was made wrong feels punitive to a kid, and if he anticipates making errors each time he practices and that he'll receive what feels like punishment creates a lot of dissonance.
Yes, this is something I need to consider and incorporate.
