@Imzadi83
Thank you for the suggestions! I'll try to get my hands on some bitter spray to try and deter the worst of it.
As for toys, we've got a wide variety: soft plushies, rope toys, soft rubber toys and hard rubber toys. He also occasionally gets to chew on a safe real bone.
I'll try and see if removing myself from the situation would help him realize what he's doing wrong, but I've noticed that pulling my hand away often just excites him. I'll also give those videos a watch.
Hopefully one of these will work, it's getting quite painful.





