A common phrase in baseball, elephant ears are simply when the pockets of a player's pants are seen outside of their slits (which happens often to back pockets which are in no way attached to the inside of the pants). Phrase made most popular by Duane Kuiper and Mike Krukow, San Francisco Giants TV broadcasters.
EBK stands for "Elite Ball Knowledge." 1 In internet slang, "ball knowledge" originally referred to a deep understanding of football/soccer or basketball, but it has evolved into a broader term for having a highly sophisticated, deep, or niche understanding of any specific topic (such as music, movies, or subcultures).
Person A: "That scene was a direct homage to an unreleased 1982 Japanese indie film."
Person B: "Wow, EBK."