rise and shine

i don't know the real meaning of this phrase.i guess,we use it to make someone cheer up when he /she is in a bad mood.am i right?

and how to use it ?

another question:
"wake up,my beauties."
here,the pronunciation of "up my"sounds like "u(p) my" or "up (m)y"?
which consonant is omited?or which have stronger influnce
than the other?

"Rise and shine" is used to say to people who are sleeping or who are still in bed and awake but sleepy and you're trying to get them out of bed. In terms of "wake up, my beauties" I wouldn't personally omit any consonant there, but if someone did I would guess the /p/ would be more likely to be omitted in favor of a longer /m/, similar to what happens in fast informal speech in phrases such as "lemme" or "gimme" ("let me" and "give me," respectively).