Derived from the slang 'bait', a person of questionablejudgement; a liability and embarrasment to others around him.
Thus, 'Baitster' refers to an individual who has consistently exhibited 'baitness', ergo, 'baitster'.
When someone stands behind you and lets you die for a REFRAG to then say 'I cant hear you down there' referring to the scoreboard, He is a Baitstain just like a cumstain on your shirt they are a piece of sh*t