Hellobee Boards

The dr brows did always leak a little, no matter the nipple speed. I think its because it does have to come out slightly easily, because sucking too hard can cause gas and other issues.
(I only know this because I had the brilliant idea that maybe my son was drinking too fast and that's why he was gassy, so I switched him to a preemie flow nipple when he was a couple weeks old. My ped told me not to, that slower flow than what they can handle is WORSE because then they are sucking and working too hard and actually swallow more air).

I used Comotomo and they leaked too if left upside down for several seconds.

It should be fine if it is a slow drip, not a steady constant drip