I have a Senegal parrot named Loki that I've had for about 3 years now. He is very sweet and friendly with me, but will attack anyone else that comes near him. No one else in my family is a bird lover, so one bite and they are scared to even get close to him again. But the issue is that it's never one bite - I'm pretty sure it's an aggression issue because he will bite and hang on and grind his beak into their hand really hard. He'll keep trying to bite over and over. If he's with me and someone else walks by and he can't reach them, he'll try to bite me instead. He also doesn't recognize me without my glasses on and will bite me like I'm a stranger. Whenever he bites, I calmly say no and walk away for a little bit, but it doesn't seem to help.
I want to try to put an end to his biting in case I'm not around and need someone else to watch him, and also so he stops biting me when I'm wearing contacts, but I don't know what to do.