bird-cage
笯 centers on a container for holding birds: a bird-cage. The given meaning is specific and concrete, with no broader abstract extensions.
笯 combines 竹 (bamboo) with 奴, which likely contributes a phonetic element. The bamboo top suggests a cage made of bamboo strips, fitting the bird-cage meaning.
The bamboo top 竹 sits over 奴 like a woven bamboo cage holding a bird. Picture a bamboo bird-cage with a small door.
For ド, imagine a bird-cage made of bamboo with a small door: door -> ド, and the cage door keeps the bird inside.
cylindrical bamboo fishing basket