Jan taught me how to cut a small X in the nipple because the hole they come with at the pet store is too small and they struggle- NOT too big though. I'd push a small drop of formula out (I never used KMar- always the recipe from Cat Fancy- it's so much cheaper- it's the right balance, and you have a big batch in the fridge that lasts quite a few days), anyway, once they taste that drop, they try for more, but often suckling doesn't happen, I pull the nipple out so they have to go after it (just a bit) which seems to make them grab and sort of stimulate the suckling. It sometimes takes several tries but I've never had a kitten that couldn't finally get it. Yes i have needed jan to come help because "It WON'T NURSE! WAAAAAAAAA!" But then for her it does! So i was losing patience is all and panicking maybe! I had one kitten that got it only for a few seconds at a time then seemed to forget, he'd cry and cry... but then he was 4 weeks old and able to eat the supplement stirred up with wet kitten food all nice warm! He did fine! (Still have his brother- Scamp!)
good luck, keep us posted!