Also known as: ふくれっ面, 「ぷー」とふくらんで
Puffing out both cheeks, forming a :I shape with the mouth. Similar to :T, except with lines at both sides of the mouth. Usually indicates that the character is Pouting, Eating, having their cheeks squashed, puffing their cheeks, or holding their breath.
Actually :I but not capitalized due to technical restrictions and may be confused with lowercase "l"(L).