When hair poofs out above a scarf (or similar apparel, like headphones around neck).
It is named after the fins near the tip of the mantle of the Japanese flying squid, which in turn takes its name from Emperor Napoleon Bonaparte due to the fins' resemblance to his bicorne.
Users on pixiv largely refer to this look as えんぺら (enpera), but on other sites such as Nicoseiga the term マフモコ (mafumoko) may also be used. This phrase in particular is a contraction of two words: マフラー (muffler, scarf) and モコ (moko, onomatopoeia for soft and fluffy).
The following tags are aliased to this tag: hair_in_scarf (learn more).