This is the entry point for reading Shinobu's whole fight against Doma as a running argument about what a thrust can and can't do. "An amazing thrust," Doma tells her on the very same page, immediately after casually stopping it with his palm — "I couldn't stop it with my hand," he then corrects himself, almost as an aside, having just done exactly that. It's a small, cutting piece of characterization: Doma is fast and strong enough to treat one of Shinobu's signature techniques as barely worth blocking properly, and the compliment lands as condescension rather than respect. A few pages earlier in this same fight, Doma diagnoses her fighting style out loud in similarly backhanded terms — clever, precise, "not something an ordinary swordsman could pull off," and still not enough.
真靡き translates awkwardly into English on purpose, and VIZ's choice is worth sitting with. 靡く describes something bending or swaying under external force — grass under wind, a flag under a gust, a person's will under persuasion — so a literal rendering would land closer to "true swaying" or "true yielding" than "flutter." "True Flutter" keeps the sense of rapid, light, back-and-forth motion (matching the visual of Shinobu's blade darting in and snapping back) while sidestepping 靡く's secondary connotation of yielding or submission, which would read strangely attached to an attack name. It's a case where the translator prioritized the technique's visual choreography over its literal grammar — a defensible trade discussed further on this hub's other Insect Breathing entries.
This technique's name also completes the same two-layer pattern found across every Insect Breathing entry on this hub: a dance category first (蜂牙の舞い, "Dance of the Bee Sting") and a quoted sub-name second (真靡き, "True Flutter"), mirroring how 蝶ノ舞 pairs with 戯れ. No numbered style on this hub uses this structure — it's specific to Shinobu, and specific to a style whose whole premise is speed and repetition rather than single decisive blows.