Usually refers to "Save the Best For Last", a teachable killer perk belonging to The Shape / Michael Myers in Dead by Daylight. (The
Halloween Chapter DLC)
This perk selects one of the four survivors as your "Obsession", and gives you
small Successful Attack Recovery Speed increase (5%) for every survivor other than the Obsession that you hit, up to 8 stacks (
40%). Often seen on basic attack killers (commonly referred to as "M1 killers") to impressive results.
"I really like
running Sloppy Butcher for the healing
speed debuff, but STBFL looks tempting too."
"Out of all of The Shape's perks, I think I prefer STBFL to Dying
Light."