(A): A well-timed, but unintentional roast; stating the allegedly true facts of a given situation; speaking truth on a matter for which you may have no prior knowledge, but it is extremely relevant to a given situation.
(B): The response to a well-timed statement and/or unintentional roast. Part of a much larger sentence structure that responds with humor to the revelation of previously unknown facts or truth that is relevant to a given situation.
When a person - gay or straight - comes out as a gainer or encourager. Gainers are sexually attracted to being fat and getting fatter while encouragers are attracted to fat and making someone else fatter. Some people are both! This is essentially coming out about a specific part of one's sexuality.
Did you hear that Seth has began coming out of the pantry? No wonder he's gotten so fat!