Both of my girls have petite facial features. That and DD1 was jaundice and very tired and lazy, I found it hard to get her stimulated enough to open wider. I had to get her really razzled up to get her gob open enough to take more in. One midwife even tricked water down her bare back, that woke her up real fast and the chompers opened wide and snapped it all up, except 2 minutes later she was asleep again and sliding off. In the mean time I persevered with the pain and would leave her on there just so she could get a feed, big mistake cause I got major damage. Second time with DD2 I learnt just to keep taking her on and off, on and off, she seemed to learn faster and this time no damage, it still took over a week though.