You just described my 5 month old daughter--from the age of about 4
weeks. Feed nicely and properly for a few minutes, let go, get mad, root
around, then refuse to relatch or to stay attatched for any longer.
Mine is also the most obstinate wrist sucking baby I've ever met! She
will stop nursing and suck on her hand. I have a pretty quick, though
not overly "strong" letdown, so she gulps and seems to fill up quickly,
then seems to want to nurse but can't be bothered. She nurses often, and
leisurely, at night and just after waking. How often is this baby
nursing?  Is weight gain still good? What I find occasionally works is
to offer my finger to suck in the nursing position, then when she
relaxes into that, slip it out and slip in the breast. Sometimes it
works and sometimes it doesn't. Since every thing else has been lovely,
I just view it as a personality quirk of my wild red-headed child.  I'm
looking forward to reading anybody else's comments!

Sincerely,
Andrea Simmons
LLLL
St. Louis MO