Louis: Wonderwall - Oasis; "Y/N, you are my wonderwall, you know that?" He sang it to you first, now you sing it together when someones in a bad mood.
Niall: Fast Car - Boyce Avenue; the way your voices mesh together perfectly on the chorus, you and him can never get enough of.
Zayn: Jump Then Fall - Taylor Swift; You're both huge fans of her music and it played on the radio and both easily fell in love with it.
Liam: Fix You - Cold Play; You both love how soft and sweet the song is, the meaning behind it got to you, and he first sang it to you when you lost your mom.
Harry: Give Me Love - Ed Sheeran; He can's ever get his hands off of you when listening to it, and when you two harmonize he's always kissing up your neck to your lips.