Hi all, We have an 11 week old doberman puppy, who 90% of the time is playful, loving and smart. On occasion though, he'll switch into a biting mode where he's fixated on biting us. When this happens he doesn't seem interested when attempting to redirect, it seems he WANTS to bite and keeps coming forward. Getting up and walking away almost certainly results in him biting calves / legs. It seems he's either; trying to initiate rough play OR he's frustrated (needs potty or sleep). He's only just had his 2nd round of vaccinations so we've only been able to socialise him with 3-4 other dogs owned by friends. He loves to chase and play with the other dogs, whipping his rear end round at them and play mouthing. Currently we're consistently shouting "no biting" and attempting redirects when possible or giving 10-15 second time outs on his pen when it becomes persistent biting. Then rewarding when biting toys. Firstly, is this normal and secondly are we taking the right approach?