We've a 6 months old boxer puppy, the last days he wanted to attack my boyfriend when he passed his food bowl. He gave a warning (became frozen) but then jumped on my boyfriend and wanted to bite him. I moved the bowl to a more quiet area there he could eat completely undisturbed. Today he got a bone, he was laying with me in the living-room when my boyfriend walked in and he rushed to him and jumped on him and wanted to bite him. He didn't want to bite hard but just say "don't come closer to my bone". Problem that he last time didn't give any warning, as soon as he saw my boyfriend he rushed to him. With me he never shows any sign of aggression, I can take any bone, toy or food from him and he don't care. It's just with the boyfriend. Question how should we work on this? When he was younger, we always gave something in exchange for a bone etc so he would see it as a "win-win situation". Also problem that my boyfriend doesn't have so much experience with dogs.