Based on the search results, an "upper decky" is a slang term that refers to a specific brand of snus or pouch nicotine called "Zyn" that is placed against ones gum behind the top lip. These pouches of nicotine are also called "lip pillows". The phrase "upper decky" likely comes from hockey slang, where the upper deck of a hockey arena is the highest level of seating. The term "upper decky lip pillow" is often associated with frat culture and hockey culture.