Morning Trucksie,
The basic idea of growing sacrifice branches is to allow a side-branch to grow out while keeping the rest of the plant under control. The side-branch will assist in thickening of the trunk.
This method is commonly used on pines. You can use it on other trees as well.
Any side-branch on your tree can be used as sacrifice branch. When selecting which branch you want to grow out, keep in mind that you will create a branch that is very thick: After removing this branch you will have a scar.
It'll take several years of work on closing the wound in the bark. So ideally you pick a branch in a spot on the back of the tree, or in the bend of the trunk.
As the branch grows, it will add girth to the trunk below the attachment point. Everything above the branch will not get thicker as a result of the sacrifice branch. Therefor this is an ideal way to increase taper: Select a branch halfway up the trunk, and you will thicken the lower half, leaving the upper half alone.
In order to avoid that all the other branches die, it is important to allow for some growth on all the other branches. So let the branches grow some 4 branches, and then trim back to one leaf. Also, ensure that the
sacrifice branch does not shade the branches directly around it.
Just let the branch grow, until the girth you want is reached. Then cut the branch flush with the trunk using concave cutters. Then let the tree grow ‘wild’ for a season afterwards which will help heal the wound site.
Good luck.