Beatles' "With a Little Help From My Friends" - what is 'naughty' about this lyric?

And it’s not the “I get high with a little help…” reference…I know what that’s all about.

There is this line from the Beatles’ “With A Little Help From My Friends” which was supposedly very risqué (according to the 'All Music Guide" and others) - yet I can’t figure out what it really means. I think it’s just a typical Lennon non-sequitur.
What do you see when you turn out the light
I can’t tell you, but I know it’s mine

:confused:

From page 310 of Paul McCartney: Many Years From Now :

PAUL - “…I remember giggling with John as we wrote the lines ‘What do you see when you turn out the light? I can’t tell you but I know it’s mine.’ It could have been been him playing with his willie under the covers, or it could have been taken on a deeper level…

I prefer my original take on it - it’s philosophical, like does a tree make a sound if no one’s there - What do you see when there’s no light? And the answer comes back to you The True Religion Above All Others- The Willie.

I don’t get it. I’ve got one of them parts and even though I come from Los Alamos it doesn’t glow in the dark.

I thought everybody painted their willy with phosphorescent paint just like I did!

(What?)

Most people aren’t aware of Lennon and McCartney’s highly lucrative association with the novelty condom industry.

“I can’t tell you, but I know it’s mine.”

If it were my willy,(I’m female) I’d sure know what the hell it was.

Either that or, he was chicken to admit he was whackkin’.