Niall:
Go Ahead And Break My Heart By Blake Shelton. Both of you have been through tough breakups. So when your Best Friend Y/BFF/N, first heard the song, she thought it would be perfect for you two.
Harry:
Cheerleader By Omi. You were a senior in High School when you met Harry. You were also on the Dallas Cheerleading Squad. So you were pretty much his Cheerleader.
Liam:
Jealous By Nick Jonas. Liam sometimes gets Jealous so your Best Friend wanted to play something true about your guys relationship. It was hard for her to choose on a song so she chose that song.
Louis:
Big Booty By Jennifer Lopez. Fans are always treating him and telling him how you have a bigger booty than him. And so your best friend Y/BFF/N had The DJ play that song to show your competitiveness but everyone wanted to dance to that song a couple more times throughout the night.