My ferret, Tigger, also did the violent shaking with my baby, Nibbles whenever I first put them together. Now that they have been in the same cage for a few days, he doesn't seem to do that anymore. They actually sleep and play together now and it's great. Tigger was also a terrible biter when I first got him. I started spraying bitter apple on my hands and arms and toes whenever I took him out of his cage. He hasn't bitten me since I did this for a couple of days. Also, when he would act all scared/try to intimidate me, I would bring out the ferretone and scoop him up and give him drops of it while I gave him lots of petting and talked softly to him. After just a few days of this, he now plays "limp ferret" whenever I pick him up and he seems to enjoy coming to me for attention. Also, the biting has completely stopped. If I put the bitter apple on, from the first time on, he doesn't even attempt to bite me.