Since you asked... I will say what I've always done. When a puppy bites or acts food aggressive, I gently take puppy by his scruff and remove him and put him aside into a sit and tell him no. I don't put my hands near his mouth and I don't reason with him. Oftentimes a stubborn puppy will get up and come back to repeat the behavior. Remove him again and repeat. I've had mostly Labradors and this didn't take long to work at all. This must begin as soon as you get puppy and you MUST be extremely firm with it. The key to the puppy learning anything is consistency and firmness. He obeys your boyfriend because your boyfriend is serious and gives off the right energy. He disobeys you because he thinks you're playing. I can't recommend you use this method because the "positive only" people of this site say it's bullying, but I don't think it is. I don't advocate smacking the little dude in his face, I'm not even an advocate of spanking him... And I definitely don't think pinning his head down is necessary... But I don't think mild physical reprimand is harmful at all. You just have to be firm.