Candy is dandy but liquor is quicker.

what does it mean and when and how can I use this sentence without being obscure?
Thanks.

I don't think you can. This isn't an anonymous 'phrase', it's a quote from a poet named Ogden Nash, and is well know as such. It's a humorous summation of advice to a guy hoping to get a girl into bed with him. If you do use it, you should properly put it in quotation marks, and attribute it to Nash.

I'm in the U.S. That is a well-known quote and it wouldn't be obscure.