You may aswell get used to the ear nipping and the earring pulling. I just say NO and take them off my shoulder. Little Bill (my budgie) is the worst at earrings and ears. once he was nibbling my earring and he hovvered in the air and was just hung on my earring he has never done it again.
If the biting on your ear hurts really bad take them off your shoulder. But if you can stand it just ignore it they will get bored because they will get no angry reaction off you.
Hope the biting on you ear lobe stops soon. Because it hurts really bad if they do it too hard!

