clicking noises in belly

OK, this may sound weird, but my baby makes clicking noises. The noise
has occured twice that I know of. It always happens when the baby is
kicking up a storm. I asked my midwife, and she said that she doesn't
know what it is, but that other women have mentioned the same thing
(i.e. that their babies do it too). Anyone have any ideas on what the
babe is doing? There is absolutely no pain involved. In fact, I feel
nothing except normal movement, and the movement never seems to be
affected by the clicking, although the baby stops momentarily (but
really not for long) after a click occurs.