My 2 year old's teeth touch too. i say 'big mouth' and reattach her when it starts to hurt. supporting her back is important (we still do cradle hold) so she is not hanging on by her mouth. Actually even if we lie down to feed, i have an arm on her back or leg to keep her in close when she is feeding.

A pillow (or towel) under his head, or your breast, might help change your position.