Hey fish girl!
Quite a coincidence that I stumbled upon your post. I just registered here and it was for my new fish tank. I am a dog person and now have fish that I don't know the slightest thing to do with!
Anyhow, first off, congrats on your new little baby Boomer. Cute name. And Second, don't let my name scare you, twocrazyrotts I picked only because they crack me up crazy.
You have the potential for a super dog in your lap! Literally! Rotts are angels if brought up right. I remember my two females at that age with all the biting! It hurts! Now I am by no means a professional; vet or otherwise, so my replies are strictly my experience. So here I go rambling... Boomer is teething at this point, so of course you should have lots of chew toys on hand for him to gnaw on. (and don't give him old socks or shoes like I stupidly did with my first one - Dallas never knew why I was angry when she ripped up a "good" sock or shoe I left laying around!) Then also remember that dogs use their mouths to socialize at a young age like that. They don't have hands so they are "reaching out" in their own way for attention. But they do need to know that you will not accept this behavior. They also are in that test-the-water kind of stage to try to figure out who's boss. So take the lead sister! Might get some flack for this but I use old school methods. Just as soon as Boomer starts nipping or biting grab his head and with one hand using your thumb and middle finger squeeze the sides of his face in between his teeth for a few seconds. He will probably yelp a little in shock or a little pain (less than his little needle teeth on your skin though) and will probably back down. Of course he'll forget this less than traumatic experience but once you do it a few times, if he's anything like mine, he'll get the point. It's the whole action, reaction thing.
Well, that's just my experience and like I said, probably will not go over well with some. But it worked for me.
Good luck and I'm jealous! Trying to figure a way to convince my husband we need another rottie!
Have a great weekend,
M