"Afterdarking" is essentially synonymous with "bleepity-bleep", i.e. it is a "family-safe" replacement for a curse word. It derives from the #sluggyafterdark chat room, which was created so that members of sluggysquad (which is a family-safe chat room) could discuss "adult" (non-family-safe) topics. Chatters in #sluggysquad began using references to #sluggyafterdark – often shortened to just "afterdark" – to indicate unsuitable content which they might be explaining at greater length in #sluggyafterdark. This eventually evolved into the use of "afterdark" as a substitute for any rude word, often conjugated appropriately (the most common conjugation being "-ing").