Here I am cutting with the u-shaped gouge. I use one hand to push while the other hand guides the tool. I always hold the tool with both hands. This also keeps both hands out of the path of the sharp blade.

The knife is a more precise implement than the u-gouge, but it takes two cuts, one from each direction, to remove a sliver of wood. Here I am making the first cut with the blade angled away from my hands.

I am using the small v-gouge, while other tools lie ready at hand.