If your BB really can't switch from nipple to teat smoothly, you can express milk and feed your BB with bottles. I did this after my son began to have teeth and did this until he was 9 mths old. :lol:
One advantage is that you know how much milk he has each time.So he won't be asking milk so frequently as he is breastfed.
If you drink enough papaya / fish soup, and have a good pump, you don't have to worry about maintaining your milk supply.
Just try your best to keep on coz' mother's milk is the best for BB.