It's an acronym for a part of the song "What Makes You Beautiful" by One Direction. It stands for: "Baby you light up my world like nobody else"
friend: I'm really sad
friend2: why?
friend: because it's always wyd and never BYLUMWLNE
friend2: I feel ya
friend2: why?
friend: because it's always wyd and never BYLUMWLNE
friend2: I feel ya
by narry4life February 22, 2021