I'm also curious about the meaning of the word "whack" as found in that "Can't You Hilo?"

There's a current African American slang word "whacked" , meaning "crazy". But I figure that has nothing to do with this song.

I'm thinking "I've always had my whack" means "I can always get girls that I want [to have "romantic relations" with]. But that guess may be completely wrong.

Anybody know what that word means?

Another verse of "Can't You Hilo" reads:
"High brown, dark brown, yeller gals, O!
Lets all go on a big Hilo."

-snip-
The first sentence describes various skin colors of Black women:
Though I've not heard this term used, I'm thinking that "high brown" means "lighter brown". "Dark brown" is self-esplanatory, and "yeller" means very light brown skin to almost White in skin complexion.

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Here's another guess about the word "hilo"-Maybe "Let's go on a big Hilo" means "Lets 'party hardy'" as people are relaxed and greeting each other at parties [hilo=greeting??]