Agree with what others have said - use the positive methods discussed on this thread and many others on the puppies board. It can take a while, but they really are effective!
I cannot believe a responsible breeder would advise you to do this... how many of her pups have gone to homes where this has been done to them, and what long term damage will have been caused by this!!!
It would be like suggesting a parent bite a toddler back who's bitten or kicked out etc...
You have come to the right place, and with positive handling, your pup will soon forgive your mistakes
he may be a little wary of you at the minute, so it might be an idea to try hand feeding a couple of times a day, so that he associates you with positive experiences...