I've had my 4 month old female for 7 weeks now, and all she wants to do is constantly nip and chew on myself and my girlfriend. We've tried pretty much every method we could find online, but none of it has worked. We tried yelping/saying ouch and walking away, immediately ignoring her when she bites, holding her lower jaw with our thumb inside her mouth then redirecting to a toy, holding her muzzle and saying no bite, and teaching her off by holding a treat in our fist and rewarding her when she stops biting at our hand. She behaves when we first start playing with her, and saying off works when she starts to bite, but after 5-10 minutes she gets excited and then nothing stops her. She has no interest in any of her chew toys, just us and our clothes. She doesn't even seem to mind us holding her lower jaw, she just twists around so she can keep biting our thumb, then when we let go she goes right after our hand again, seems to just make it worse. In the last couple weeks she started rolling over and acting like she wants her belly rubbed, then when I do she starts kicking and trying to chew on my hand, like she's luring me in. She's very smart, only took 2-3 tries to teach her sit, stay, come, and off, and she seems to know that she's not supposed to bite/chew on us, but when she goes into play mode she's intent on doing it anyway. Yelping and ignoring her also just seems to make it worse, she'll grab hold of our pants when we try to walk away and won't let go. It's to the point where we can barely have her out for 30 minutes before the biting is so bad we can't do anything with her. Any ideas? Could it be a dominance issue or something?