Mark H. sends this in: “I think he meant Achilles tendon. I don’t think “Achilles heel” is a medical term…”
JMcAndrew sends this in: “I think Dennis is only supposed to be at the most 5 or 6 years old. He seems kind of young to be having sex talk with, also what did his father say to him that confused him like this?”
Comics I Don't Understand 
With Dennis, remember that “The Birds and the Bees” is more about avoiding the issue, than it is to explain where babies come from.
Dennis is canonically “five anna half”.
That said, it’s never too early to start talking about how babies are made.
“Achilles heel” is correct, not tendon, because he is making excuses and doesn’t know what he is talking about. That’s the joke.
I never got “the talk”. When I was roughly 12, my mother handed me a book she’s bought from Our Sunday Visitor, a Catholic newspaper, and said to let her know if I had any questions, clearly hoping I wouldn’t have any questions. The first sections of the book talked about flowers, featuring birds and bees.
Of course, the phrase “the birds and the bees” is likely used because of the nice alliteration, not because the birds and bees are procreating with each other. That would be as unlikely as tearing your Achilles heel.
I got “the talk” early, before we moved to Canada in 1969 when I was 8.
There’s a street there called “Regina”, pronounced with a long “i” sound, so it rhymes with a certain other word. Shortly after we moved there, we were driving on that street, and my dad the linguist asked me if I knew what “Regina” meant.
After a pause, I said tentatively, “I thought it was part of a lady?” He was nice about it but (quite reasonably) very amused. I had been VERY puzzled as to why they’d named a street that!
That was 55 years ago and it still makes me laugh.
I never understood how learning about the “birds and the bees” was supposed to help anyway – it’s not like there’s anything in common between them and human reproductive practices.
waltmorris: If you get to a high enough altitude there is commonality: binary sexes, eggs, etc. I assume the origin
(https://en.wikipedia.org/wiki/The_birds_and_the_bees#Origin_and_history)
was intended to get things far enough away from, you know, human dangly bits that the general idea could be understood without that level of detail. And farm kids (and many others with pets) would already know lots of those details from observation, without necessarily understanding what it all meant, so “birds and bees” might fill in those gaps without, again, any icky human references.
All of which reminds me of an old joke:
Farm boy brings his cow over to another farm to be bred. He and the girl from that farm are sitting on the fence watching the, um, festivities. The boy looks over shyly and says, “I’d sure like to be doing that…” and the girl answers, “Go ahead, it’s your cow!”
Which reminds me of another old joke.
Farmer Jones had two cows, a white cow and a brown cow. He borrowed a bull from Farmer Smith. Then he set his young son Luke, about Dennis the Menace’s age, on the fence, and told him to watch them and come tell him if the bull did anything. Then Farmer Jones went into the house.
A short time later, Luke burst into the house, very excited, and said “Paw! Paw! The bull ****ed the brown cow!”
Well, unfortunately the parson was visiting for tea, as always happens in these jokes, and bit a chunk out of the teacup. Farmer Jones took Luke aside and said, “We don’t say that word. Say that the bull ‘surprised’ the brown cow. Now go out and keep watching them.”
A short time later, Luke burst into the house. “Paw! Paw!”
His father interrupted him. “Let me guess, Luke. The bull surprised the white cow.”
Luke said, “He shore did, Paw! He ****ed the brown cow again!”
My maternal grandfather was a farmer and raised cattle, polled Herefords. He was telling me once about having to keep a bull. He said you could own one for years and never have a problem, then one time you turn your back and he knocks you down. He was happy to move to artificial means.
That Dennis cartoon looks confusingly suspect. Back in the pre-computer day cartoons would be Xeroxed, faxed, traced, and otherwise visually degraded as they journeyed from desk to desk, ending up much like this. But the clean, authentic-looking caption lettering looks like it was grafted from a much better copy. If somebody had that clean a copy of the caption, why affix it to a cruddy copy of the drawing?
I don’t see any difference between the caption and the rest of the panel, quality-wise.
“Achilles Heel” is a malapropism, and those can be funny. Someone told me about a door-to-door salesman who, meaning to ask the prospect to sign the contract by saying “put your John Hancock right there”, would say “put your John Thomas right there.” He was unaware of the problem until another salesman educated him on the difference between John Hancock and John Thomas.
There is an old Heinlein novel, The Star Beast. The main human character is named John Thomas, a name given the to the oldest male in his family for many generations. At one point, the titular Star Beast, who the family has thought of as a pet, states that the reverse is true and that she has been “raising John Thomases” for generations Many stories purport that this was a joke by Heinlein to sneak a ribald reference past the censors.