well not wanting to sound a dunce here - but I think I just need a little 101 on the differences here

Honey is 19 weeks today. She has been with us for just 2.5 weeks as we rehomed her.
She has settled in very well and is generally very calm and nicely playful.
She is a keen chewer but is very good at mostly sticking to her various Kong toys! though my slippers get the occasional nibble if I am not careful

From suggested reading on this board I have read Dr Ian Dunbars Before and After getting your puppy and I am little confused about the bite inhibition chapter.
He suggests that in order to teach bite inhibition she should be allowed to mouth so we can tell her when she is biting (did i get that right?)
What I want to know (dumb moment!!) - what exactly is mouthing? I am currently allowing her to hold my hand in her mouth and when she is applying very gentle pressure I say 'Gently gently, good girl " over and over. I can feel her teeth when she is doing this but figure there would be no way not to feel puupy teeth doing this! The moment she exerts any element of pressure immediately do a mock cry and remove my hand a mock cry. we then continue and if she does it again i leave the room for a few minutes.
Am I doing this right? Is there where we should be at this age? When I read the book it is based on having puppy from 'new',as as we got her at 4.5 month stage I am not sure if I should be approaching differently at this stage?
She does not initiate mouthing very often, but after getting excited does do play biting which I immediately mock cry at and then ignore her for a short while.
Last night she was very excitedly chewing her kongs but then came to sit with me and started to chew a cushion. I told her off and she growled at me and went as if to bite me. I told her 'off' and then ignored her....and she didn't do it again.
Any tips on if this is right or wrong, expected or unexpected would be appreciated.
As we have two children ( 8 and 5) and want to do this stage correctly, and someone has planted a seed of worry in my head that this may have been a reason for the previous family to get rid of her (they cited youngest childs allergies as the reason, but i alwasy thought there as more to it).
We have been to one puppy training class so far which focussed on sit, down and stand. So I will ask the lady next week too. But thought I woudl also ask the cocker experts

Thanks
Beki