I've been teaching Edwin how to use a knife.
He wanted to sharpen the end of a stick. He'd found it in the park while playing with his friends, then brought it home and got busy with a Sharpie. The stick is now his Commander Dagger. It needed to live up to its title, so we went and sat on the steps leading down to the park outside our house. I was drinking a can of lager, and grabbed a beer mat to place over the aperture so any dipsomaniac fruit flies would not glide in and then giggle and then drown.
We perched on squished cherries on the steps. I handed him our vegetable knife (my Swiss Army chum was AWOL.) I showed him how to hold his thumb underneath the wood, the deftest angle at which to hold the blade and -- all together now -- to sweep it away from his body. Tapping the beer mat on my can, I watched him.
Thing about sitting with your boy, whittling sticks, is that it puts a big fat jaunty arrow above your head: "Dad and son". Even more so than if Edwin were wobbling on a bike, an adult hand disengaging from the saddle. Heck, any hick uncle can learn a kid how to bicycle. But endowing a twig with enough of a point to penetrate the fleshy parts? Father.