I just point my elbow at him and have my fist pointing backwards almost like having my thumb touching my delt/trap(make sure to have your hand/forearm over your ear and shrug your shoulders a bit to protect your chin). his punch should land on the meaty part of your outer arm/forearm... You should be able to see his puch coming a mile away, If you use this guard make sure to step in and hit him with something. If you don't plan to step in and hit him right after his puch you might as well step back and dodge it or just duck it. No need to take the risk of it sneaking in unless you are going to capitalize on the risk.