Basically, certain Oni charts in the Taiko no Tatsujin series branch out their notes into different difficulties depending on how well you play: it starts at "Standard", then upgrades to "Expert" if you play well and then "Master" if you keep this performance going. If it were to be implemented in osu!lazer, it would be under the "Effects" tab in the Timing section, where charters can choose where to branch out the notes and at what level. Furthermore, they should be given the option to test out each branch individually in the editor itself, and not in the editor's test play function since the latter doesn't have an autoplay key like normal osu does.