There was a joke I first read in 1978 or so that described three Indian squaws; one gave birth to a boy on an elk hide, one gave birth to a girl on a deer hide, and the third gave birth to a boy and a girl on a hippopotamus hide. Thus, the squaw on the hippopotamus equalled the sum of the squaws on the other two hides.
About ten years later, there was a big CLICK! sound in my head.
Actually, the phrase is “express written consent”.
I dont get it, theres no hippopotamus in North America. 
I can’t understand why you guys are seeing any sexual subtext to it at all, nor is it a particularly subtle joke:
Bart: Wow, you can do anything out here!
Homer: That’s right. See that ship over there? [points to a ship with a large satellite dish on it] They’re rebroadcasting Major League Baseball with implied oral consent, not express written consent – or so the legend goes.
Implied…
ORAL…
…consent.
It’s ambiguous. We may have to wait for the Season (whatever) DVD set to come out to hear the real story.
“Take my wife. Please.”
BWAHAHAHA! Now I get it!
That’s how I like my double entendres. Pure and simple.
“. . . do not touch Willie” . . . not sexual.
Yes, “willie” is a slang term for dick, but it also happens to be the name of the janitor. Why would Homer think it would be a good idea not to touch his willie? It makes no sense as a double entendre. Rather, Homer knows who Willie is, and doesn’t want to touch him . . . which would be reasonable.
I still think the makers thought about penises and giggled when they made that joke, VarlosZ.
What’s ambiguous about it? Does the word “oral” invariably suggest a double meaning to you?
Do you giggle like a schoolgirl when you say the word “titmouse”?
The joke doesn’t have to be completely transparent to the character to be a double entendre. To Homer, “Do not touch Willie” was just good advice. It was also funny to US because it said “do not touch willie,” haha, it’s a sex joke. Just because Homer didn’t get it doesn’t mean it wasn’t a joke. He’s not that sharp. 
Giggle He said titmouse. snort
One joke from Monty Python that no one seems to catch.
In the dead parrot sketch, the parrot is referred to as a Norwegian Blue.
How many parrots do you think fly around Norway?
Obviously one. How else does it show off its beautiful plummage?
[Norwegian Blue Hijack]
Check out this plumage here. For some reason I find it nearly as much fun as the original sketch.
I think it’s this bit that pushed me over the edge:
Praline: alt.4000.volts.!voom.!voom.!voom
Sorry. Carry on.
[/NBH]
Yes… I do.
Perhaps a swallow carried it there. . .?
What? A swallow carrying a Norwegian Blue?
Wonder what its air-speed velocity would be, laden as it were with a Norwegian Yellow… no Bluaaaaaaaaaahhhhhhhhhhhhhh!
[chortle]The plural is titsmice, actually. The collective noun is a disneyworld of titsmice.[/chortle]