Help with this song please? :)?

I have been going crazy looking for the name of this song Its at the
start of Season 5 Episode 19 (season 6 Episode 9), its when the
episode name comes up "Mr Right Now" and plays till you see the hand
car wash at the start.
Lyrics go : when the lights go off ,
its like we were still living ,
i love how she answers when i get to questioning ,
who's is this who's is this!

Any ideas at all? would be really helpful! :) thank you.