A phrase used to imply that someone is really cool, awesome, and amazing. This person is pro at life. He/She usually has a long list of talents, but is often known for one specifically. When a person uses this phrase to describe themself, they are a fag.
This phrase stems from the fact that on hot summer nights, people often flip their pillow over on to the other side because it is cooler since their body heat has not worn off onto that side.
Kyle got lucky and swished a shot from half court and /thought/ he was cooler than the other side of a pillow. Shawn however drains half court shots constantly and we all knew that it was Shawn who was really cooler than the other side of a pillow.
(I have written more definitions under the name "I listen to Indie Music")