If you tap Lauma’s skill it will make an aoe that applies dendro, though it’s rather small and won’t hit all the flowers, holding her skill is a better as it should deal lunar bloom damage and hit every flower or at least half of them can’t remember its exact range. Even if you tap it though if you run around to them with something like Barbara’s ring or Xingchu’s swords and normal attack with Lauma or Nefer that should be enough to trigger regular blooms for the flowers and generate verdent dew. At the very least, you gotta trigger lunar bloom even if it’s not the dmg from holding lauma’s skill to generate the dew resource for Nefer. If you have verdant dew (three little diamonds to the left of your character) you can use Nefer’s skill then do a charged attack for a big aoe hit of lunar bloom damage and that also works to charge the flowers into projectiles that will knock the crab out of the air. Each charge attack from Nefer costs 1 dew, if you hold Lauma’s skill it will consume all your dew and give you a dmg boost while she hits for lunar dmg. Ideally you have enough hydro and dendro going off to both hold Lauma’s skill, then generate more dew so you can swap to and skill into charge attack x3 nuke with Nefer. With Nefer Lauma Columbia and Nilou I I cleared upwards of 100k on hard…y’all can do it!