Hi, We have a 12 week old pup. (got her at 9 weeks). Maya is a tri-colour. We are very happy with her. She's a bundle of energy and fun. Don't know what else to say right now but hope to get to know some other people and read lots of advice.
Looks like you will have your hands full! The video made me chuckle, especially how quickly it happened and how the pup looked excited to make it to the sofa!
Most people incorrectly use the terms dominant and dominance with regard to dogs. Here is a good blog post by Dr. Sophia Yin on the topic.
http://drsophiayin.com/blog/entry/dominance_in_dogs_is_not_a_personality_trait
Adorable face - probably a devil in hiding :p
If the biting is clearly play biting a firm NO should work (and see previous comments). If more serious then try bitter apple spray. You definitely want to stop this type before it gets out of hand.
Mine (3 yrs old) occasionally will bite (gently and really just a mouthing) when trying to get my attention to play. But you can tell from her expression that she knows she did something unacceptable.
Consistent training is the most important thing you could do.
