cut straight down the bark of a "finger" size twig (or smaller) about an inch and a half cutting through the bark slightly into the wood.
 
 
 
 

After your first cut, cut across the plant at the top of your first .  still slightly into the wood .

When finished with the " t "
 
 
 

cut, you will need to confirm that the plant is hydrated enough to continue.  Peel a bit of bark with your nail.  If it doesn"t slip (peel away from the wood cleanly) then STOP , water the stock regularly for at least a week, then try to see if the stock is
 
 

hydrated enough to slip with another " t " cut.