Aggressive ferret?

My female ferret, Bean, is very sweet but has a nipping issue and is aggressive with strangers. When I first got her I did my best to nip train her, and now she doesn't bite- me, at least. When playing with other people she's way more aggressive and holds down on her bites. She doesn't show any signs of fear, no puffed out tail or hissing. She usually comes up to said person and then bites them, dooking and either flopping away or going in for another bite and holding on. She hurt my mother quite a lot, drawing blood once or twice. I try to introduce my ferret to her, letting her sniff my mom or have them play with eachother, but when she's not paying attention Bean will sneak up behind her and bite her hard. My mom told me recently she grabbed onto her with her claws to bite her! How do I help stop this, because I don't want to have everyone be scared of her.

She knows she cannot bite me and get away with it. My guess is that my mom makes a pleasant "squeal" when Bean bites her, and probably finds it funny and bites her more. I know parrots are often like that. I don't know why she's doing this, because it seems only borderline playful and gets into aggressive.

She needs to be trained not to bite. If she can bite you without consequence, she will do the same to others.  Start with holding her in a safe hold and a loud NO BITE!, then put her in a carrier if you have one for no more than a few minutes.  It's best not to use their cage for punishment, but if that's al you have... You have to be consistent with this. If this doesn't work after a couple weeks or so, I have used the NO BITE! scruff drag technique with much success, tho there are those who say only scruff when necessary, like to give meds.  With a couple hard cases, I have actually scruffed them with my own teeth and dragged across the floor out of frustration, lol.  It worked.

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