First off, to unlock this you need to earn Rep (finish the final songs with four stars or more) on all the other Crew Challenges.
By master, it means earn five stars on all songs in the Glitterati's Crew Challenge.
The songs are (Number indicates difficulty level stated in game):
Born This Way (5) (as the final, unlocked after 16 stars are earned)
Like a G6 (5)
Body to Body (3)
Bad Romance (5)
Oops (Oh My) (3)
The songs can be broken down from within the song selection in the Crew's setlist, so you can have a good practice/warm up. The higher difficulty songs are a little hectic and overwhelming to sight read, but break it down is a massive help.
This IS stackable, so pop this and you'll also get:
Or go for Hard, and pop:
as well as the two for medium and easy!