Church-Bell is a Victorian slang phrase originally used to reference talkative women. Though slightly sexist at the time, the term usually now covers all genders.
“Your wife is a real church-bell when it comes to badminton.”
“So what? You're a real church-bell when it comes to knock-off pizzas and pirated movies, but you don't see me complaining.”
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."