judging by how i googled "osu mania snickers method" and found a video smth like "i got 9X.XX% on INSERT CHART HERE with the snickers method!" or smth to that effect its probably a specific way of maniping that tries to maximize acc (manip is where you hit notes slightly incorrectly to maximise acc because you nerf pattern basically)
copy paste link to my advicr thread lol free advice. ask questions (ideally mania, but ill try attempt other game modes) and itll be a big collection of advice and itll be organisied