I was reading a book on flop Broadway musicals and it says:
OK a little help?
Show and year?
It sounds like the ‘‘salt shaker’’ might’ve been a tad phallic for her liking?
It’s a carpe diem statement - I wanna party while I still got some partyin’ left in me. Seems obvious…?
Maybe it was just because it’s such a terrible lyric.
But “shaker” could refer to the same thing as the later “shake your booty.”
It means she wants to get fucked a lot. Some people consider “fucked” to be dirty.
You use your hand to move the shaker up and down and then a white substance spews out the top?
/reaching
I think it’s a meant like “sow your wild oats” which I guess she was uncomfortable with. Clearly it was a different time 
It means Mary Martin needed to get laid. JOKING
Seriously, it’s like the others said, it’s about being decadent.