@tattooedmami, what do you mean press the bottom the bag?
I've tried dr.brown avent and tommee tippee with my 3 kids and now with the baby I'm going to try Comotomo bottles and Mixie for when I travel ... Mixie are a time saver and comotomo are amazing I love the way they feel how flexible they are and how much they resemble a breast ❤️
My son only took nuk wouldn't use anything else
I purchased DR Browns glass bottles. I have a couple Avent bottles too.
YouTube mixie bottle