Yes, it's Justin Bieber's take on the old "Eenie Meenie Miney Mo" rhyme. The rhyme is nonsensical - no need to think about it too much! - and used to make a "random" choice. You point at each of your options for each word you say. The last "Mo" will decide what you choose. So JB is saying that "shorty" (the girl... because she's short. No, really.) just chooses her boyfriends randomly, she doesn't care. And advice to the boys... if you catch a "bad chick", you'll know because she "holla", so you can let her go. Make sense? :) Ironically, I think whoever re-wrote those lyrics has thought too much about a kid's rhyme! ;)

From Wikipedia: One major theory about the origins of the rhyme is that it is descended from Old English or Celtic counting, as can be seen in the East Anglian Shepherd's count, "Ina, mina, tehra, methera" or the Cornish "Eena, mea, mona, mite".[1] The first American record of a similar rhyme is from about 1815, when children in New York are said to have repeated the rhyme: Hana, man, mona, mike; Barcelona, bona, strike; Hare, ware, frown, vanac; Harrico, warico, we wo, wac.[1] The rhyme seems to have been unknown in England among collectors until the late nineteenth century, although it was found by Henry Bolton in the USA, Ireland and Scotland in the 1880s.[1] He also found a similar rhyme in German: Ene, tene, mone, mei, Pastor, lone, bone, strei, Ene, fune, herke, berke, Wer? Wie? Wo? Was?[1] Another possibility is that the British occupiers of India brought a doggerel version of an Indian children's rhyme used in the game of carom billiards: ubi eni mana bou, baji neki baji thou, elim tilim latim gou.[3]

We used it to choose between 2 or more things. Or to decide who has to do something. Kind of like playing "Rock, Paper, Scissors. Here's how we played it. You say the following rhyme and alternate pointing to someone with each syllable: Eenie meenie minei moe. Catch a tiger by his toe. If he hollers make him pay Fify dollars every day. And you are not IT. Whoever you're pointing to when you say "IT" is out (or excused).

Lol, this is rather a children's counting rhyme Sonia. It consists of similar sounding NONSENSE syllables like the Eenie Meenie ones. They have been modified many times, once catching a tiger and in your version 'a bad chick' ;)