Puffing out both cheeks, forming a shape similar to :T with the mouth, 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 (with serif) but not capitalized due to technical restrictions and may be confused with lowercase "l" (L).
The following tags implicate this tag: ;i (learn more).
