fragrance
馝 centers on a pleasant, pervasive scent: fragrance. It is a rare character used specifically for aromatic qualities.
馝 combines 香 (fragrance) with 必, which likely serves as a phonetic component. The exact historical development is uncertain, but the structure suggests a phono-semantic compound where 香 provides the meaning and 必 hints at the sound.
The left side 香 means fragrance, and the right side 必 looks like a heart with a slash, as if the scent is so strong it pierces the heart. Imagine a fragrance that is unforgettable.
For ヒツ, picture a fragrant flower that hits you with its scent: hits -> ヒツ. The fragrance is so strong it hits your senses.