male kit ferret, nipping vs. playing

Question
first thanks for your advice! we have a 4mon male ferret, had him 6wks. first we would let him nip/bite us when we played with him (while waiting for Ferrets for Dumbies book to arrive via mail which told us NOT to do that)..then we moved to using a towel or toy instead of our hand for play..but like all ferrets, he loves to attack w/ an open mouth/teeth showing and run..he will touch us, usually 'nip' and run, etc... over the last week i have been more actively trying to train him not to bite. doing all the things recommended...here in is the question what to do when...
1) it almost seems like he BITES MORE when i get stern & scruff him and holding him 'still' OH BOY!! that is a struggle waiting for him to 'calm down'.. he only get more upset. AND when i give him time outs, some days it is like he doesn't get out of the playpen as much as he should b/c i put my hand in, he nips it, i walk away for 1mins, i come back all nice, put my hand in and talk sweetly, he nips, i walk away, etc.. when he doesn't and i pick him up i hold and praise him, but inevitably he can't go more than 10 seconds before he is nipping to get out of my hands...
2) MOREOVER... HOW do i know if I am OVER CORRECTING... when he runs up and semi-nips with no clamping down.. is that OK?? or am I now teaching him that IS OK, ONLY to have to try and UNDO that behavior later??
please help! we want to be very responsible ferret parents..
thanks! g


Answer
First, congratulations on getting the book!  Second, your ferret is only 4 months old.  Much like puppies, ferrets test the work with their mouths until they learn biting is not Ok with people.  They play VERY rough with other ferrets and don't always realize we get hurt easier.  That being said, with some ferrets time outs and scruffing only seem to initiate play, so they aren't always the best policy (with some they work wonders).  Since he is so young, I recommend yelping very loudly when he bites.  If he bites you, don't give in.  Wait for him to give up, then continue to play or work with him.  Ex: if you pick him up and he bites you, don't put him down until he stops.  If you reach into his cage and he bites, don't move your hand until he stops.  I know it can hurt a bit, but as soon as you pull away, it is like saying "game on" and now he wants to chase.  Until he is a bit older (maybe 5-6 months) don't offer him many opportunities to bite.  My youngsters tend to bite toes, so I either walk in knowing my toes are about to be bitten and since I don't react, they soon give up or I wear shoes that don't expose my toes.  
I believe that they can learn bite inhibition, so not correcting him if he runs to you with his mouth open and semi-nips is fine.  Semi nipping isn't biting.  Make sure he is getting enough enrichment and exercise too since too much stored energy may be leading to the biting.  
Above all, be patient with him.  He want to play, but is learning how to play with a human and not another ferret!  With love, patience, and kind treat giving hands I have rehabilitated some serious biters.