Earlier quoted context omitted.
Totally irrelevant, but a related fact in this vein: I recently learned "尻" via WaniKani (a popular SRS system to help learn kanji), and the mnemonic they used to help you remember the reading of this kanji/vocabulary (お尻) is now inspired on Apple's Siri: https://www.wanikani.com/kanji/%E5%B0%BB > Now that you have nine flags inside your butt, you have to get them out. But, you don't know how to. So you ask Siri (しり…
No: 尸, the radical of 尻 doesn't mean "flag" -- it means "corpse". Notice that many of the characters with the 尸 radical refer to defilement, excrement or death.
I don't entirely agree with that system, so I often look up the individual radical meanings anyway and add a synonym, but that's Wanikani's method.