Short for "big congratulation." You might use it to informally praise a coworker for their promotion. Use it anywhere you might otherwise say, "good job."
This dude protected the universe yet was made a meme. He's dead to due cancer that sly son of a bitch (cancer not big nibba). He was big on earth but he will be bigger in heaven.
Popular urban legend centered around Slendermans hood cousin Big Dick Randy. He prowls the sidewalks disguised as a granny on Halloween night snatching ass cheeks and candy from kids. Only advice survivors have to offer from their encounter with the ass slinging snatcher is "hide your daughters and hide your sons"
Mom: "Where is your ass and where is yo candy?"
Son: "Mama...it was Big Dick Randy!"