Any parent probably invented the equivalent of one within the first six months of their kid being born - but I guess this is one of those things that are bloody obvious and desired, but not supposed to ever become products, like pacifiers on an elastic band.
> During self-feeding, the baby is not able to control the flow of fluid. The fluid will continue to flow even if the baby is not swallowing. This may lead to choking.
Eh? Nothing comes out of the bottle if the baby isn't suckling. The baby is able to control the flow of fluid very easily.