I like this point. I often attack it with my chin. Works very well.
A cool variation on the technique would be to stick fingers in this point and thumb behind the shoulder tendon (GB 21) It makes for a good seizing technique. Also try this point with K27 or St 13 both below the clavical.
A good attack to the brachial plexus gives a good numbing jolt to the whole arm.
The older I get, the better I was!