Just googled and found this on a "fun trivia" site... https://www.funtrivia.com/askft/Question16812.html

McGruff says:

In the game of craps the slang term 'Little Phoebe' refers to a roll of 5 on the dice.

Sat Feb 23 19:14:08 CST 2002

McG says:

Unfortunately, the term doesn't appear in the dozens of sites which come up in a search of 'crap terms.' The statement I found uses the word 'slang' which may be the problem. Perhaps it's not official, don't know personally. Here's a list that does include 'Phoebe' among other terms that are not on standard lists.

link http://www.bigempire.com/vegas/vegasana.html

Sun Feb 24 02:13:40 CST 2002