From Pineapple-Oreo McFlurries to Mashed Potato Burgers, international McDonald’s menu items can get all kinds of weird. But one specialized item at McDonald’s locations in Japan is more peculiar than all the rest.

The straws at McDonald’s locations in Japan are designed to make you feel like a newborn sucking down breast milk instead of milkshakes.

Rocket News 24 dug up definitive proof of the McDonald’s milkshake-mammary connection. In a book written by McDonald’s Japan founder Den Fujita, titled Den Fujita’s Business Strategies 2: Overwhelming Business Strategies, the businessman writes,

“When humans drink something, the speed that produces the most delicious feeling is the speed at which babies nurse…McDonald’s straws are designed so that when used with a shake, the speed will be the same as that of an infant drinking breast milk.

As long as we can still get a large milkshake for under $3, we’ll be happy to drink it at whatever pace the straw allows.

There have been no reports discussing whether McDonald’s uses the same straws in countries apart from Japan. Regardless, we’re going to assume that McDonald’s in America uses the same breast-feeding straws, because we deserve peak deliciousness too.

[via Rocket News]