When they won't open up wide

Count Choculitis

One of my twin boys has a great latch and opens his mouth real wide.  The other boy is one of those nibblers who will barely open his mouth at all -- and just takes the nipple and no areola and kind of sucks it into his mouth rather than latching on with one big "aaah."  I asked my pediatrician how to get him to open wide and she gave me the usual speech about brushing his cheek with my nipple or putting the nipple under his nose.  Neither thing works.  He refuses to open.  The only time I can really get him to latch on right is when he's screaming and frustrated and then his mouth finally gets wide enough to shove it in.  Sorry for the brusk language.  Anyway, does anyone else have any tricks for getting a baby with a poor latch to open up?