There was a test done by a woman for one of the magazines. She used her husband as the sample. Every other day she would have him eat a specific diet. One day broccoli and asparagus. One day, fruits and juices. One day pizza and beer. Then she would give him head in the morning and document it. It was pretty funny. Pineapple juice was at the top for sweetness, dairy products were not good, asparagus bad.

And, in my experience and hers, lots of coffee is very bitter.