From what I learned from an OLDER post, party shuffle is like a DJ kind of thing. When you have the option "party shuffle" on, it sets a short list of songs, 10 songs, and places them in a list. You can make a "quick change" to this list, just like a DJ would with a request and such. To access this list, start playing a song and in the "Now Playing" screen, touch the bulleted-list button (it's the 4th one from the left, where there's the musical note button, replay button, and twisted arrows one, and then this one). From there you can, like i said, make a quick change to the list if you want a specific song to come up sooner.