When you feed a baby, you tend to unscrew the bottle to remove the vacuum effect and make it easier. Some of them are even marked to indicate the intensity of the flow.
Source: experience feeding and buying baby's bottles.
edit: As a teen, you probably didn't have the same incentives, you didn't have other things to take care of in parallel, your jaw was more developed, and a tightly screwed bottle will hardly drop anything if you don't shake it, so you could lay down in any position you wished, and take as long as you wanted.
It's not about the vacuum effect in the bottle, it's about how the nipple is constructed. When you suck on the end, the "neck" closes because of the pressure and won't let more milk flow. I'm a bit hazy on the mechanics because it's been a while, but I'm very sure of the end result.
I imagine you can easily try it and report back if you have quick access to a bottle, maybe you can shed more light on this.
Source: experience feeding and buying baby's bottles.
edit: As a teen, you probably didn't have the same incentives, you didn't have other things to take care of in parallel, your jaw was more developed, and a tightly screwed bottle will hardly drop anything if you don't shake it, so you could lay down in any position you wished, and take as long as you wanted.