This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 褜 is uncertain. It visually combines 胞 and 衣, but whether this is a phono-semantic compound or a later formation is unclear.
The top part 胞 suggests a wrapping or enclosing, and the bottom 衣 is clothing. Picture a garment that wraps around like a protective covering, though the exact meaning is uncertain.
For ホウ, imagine a protective garment that howls in the wind: howl -> ホウ, as the wrapped clothing flutters noisily.