Am I resigned to “sittin’ here la-la, waiting for my ya-ya”?
Or am I supposed to “get the ya-yas out”?

What are ya-yas, anyway?

sounds like getting your rocks off or getting a groove thing on. Sounds like having sex but could mean getting loaded. Depends on what you really want to do at the time.

Just for your idea…the song sounds basically like a double meaning. His ya ya is his girl’s nickname but he wants to get his yas yas…etc. Try Chuck Berry’s My Ding a Ling for another example. A gift he receives as a child that he loves playing with and calls it a ding a ling. I grant you a stanza “My Ding a ling My Ding a ling I like to play with my Ding a Ling” A fave with the frat boys

Ya-ya is what your Mojo rests on when it rises.

“When the going gets weird, the weird turn pro.”
Hunter Thompson

That’s MR. Mojo, to you, pal.
–Jim Morrison

I always thought that he was sitting in the la-la (just moping around) waiting for his ya-ya (his love interest).

It may sound funny but I don’t believe she’s comin’ at all, no-oh.

“Anything is peaceful from one thousand, three hundred and fifty-three feet.”

I’d heard once (perhaps in one of The Straight Dope books??) the theory that “ya-ya” was nothing more than his grandma, seeing as how the Greek nickname for such a lady is ãéáãéÜ.
Don’t know what his grandma was up to if she wasn’t comin’, but hey, grandmas are allowed to do that.

Cave Diem! Carpe Canem!