This man is the bee's knees . . . he is the wasp's nipples.

I tell my hubby all the time that he’s got bee's knees and a bumble butt.  Now, don’t go thinking that’s insulting . . . I actually think his knees and his butt are quite cute . . . they are terms endearments!

If you’ve heard the expression, you know that if something is the bee’s knees it is something good . . . of superior quality

What surprised me is how old the saying is . . . it first appeared in print over 200 years ago!  Originally it was used . . . appropriately . . . to describe something that is tiny  . . . you know, like bee’s knees?  How and when it could have evolved into meaning something excellent, I don’t know.

Another thought is that the bee’s knees may actually refer to Bee’s knees . . . Bee Jackson that is.  Who is Bee Jackson, you ask?  Bee is a dancer from the 1920’s who popularized the Charleston . . . you know, that knee knocking dance?  Apparently, she had some darned cute knees . . . and knew how to use them!

My favorite is this . . . "b's and e's" was shorthand for "be-alls and end-alls" . . . b’s-n-e’s . . . bee’s knees.  At the very least it’s an interesting theory.

“This man is the bee's knees, Arthur, he is the wasp's nipples. He is, I would go so far as to say, the entire set of erogenous zones of every major flying insect of the Western world.” 
― Douglas Adams, So Long, and Thanks for All the Fish a quote from the fourth book in the Hitch-hikers Guide to the Galaxy