Another one from the Gōdanshō 江談抄, while I have it down from the shelf (specifically, Yamane Taisuke 山根對助 and Satake Akihiro 佐竹昭広's 2005 edition for Iwanami Shoten's Shin Nihon Bungaku Taikei series). This one is attributed to "江相公", "Associate Counselor [Ō]e", which Yamane and Satake note might be either Ōe no Asatsuna 大江朝綱 or Ōe no Otohito 大江音人 (Asatsuna's father), but probably the former since the notes on the next poem unambiguously refer to Asatsuna with the same terminology.

The context: "On growing a mulberry tree under the southern staircase."

莫言撫養猶如子 此字反音是息郎
Don't say I care for and raise it as if it were [my] child/ The fǎnqiè of the character ["mulberry tree"] is "son-boy"

"Mulberry tree" is written 桑, sang in the Baxter/Sagart reconstruction of Middle Chinese. The Kangxi Dictionary gives the pronunciation instructions "息郎切", meaning "initial from 息, rhyme from 郎". In MC again, these were sik and lang respectively: s- + -ang = sang. (This also works if you break up the current Sino-Japanese pronunciations, but Mandarin has changed too much.)

Now 息 originally means "breath", but eventually developed the meaning "child" (Kroll marks this as a medieval meaning). Meanwhile 郎 was a respectful term for a gentleman, then for a youth in general, finally coming to imply "son" (this may be Japan-only). So this poem is one big dictionary joke: Of course I treat my mulberry trees like my kids! The two words used to explain the pronunciation of the very word "mulberry tree" imply "son"!

A further note to this poem says:

時人美之。妬能人曰く、先思此句被栽之。相公聞咲之。

People at the time praised this [poem]. A person envious of [the author's] accomplishment said, "[He] thought of this poem first and then planted [the tree]." The Associate Counselor heard this and laughed.

Notice that the esteemed Associate Counselor didn't deny the accusation.