Each person’s ear anatomy is unique. That means that getting a good seal in the ear can be difficult if designed for one size fits all.
The ear tip on Buds actually swerves when pressure is applied to it. What this means is that when the bud is placed into your ear, it makes very slight adjustments to locate itself in the proper direction for your ear canal. This is great for fit and stability, it helps improve the quality of the seal to the ear and as a result helps to increase the quality of the sound.
The best thing about it is that you do not have to actually do anything to make this work for you. Just put it in the ear and let the buds do all the work.