Songfacts®:

• The Haim sisters say this track is inspired by the way their generation uses their phones, specifically the phenomenon of the "u up?" text, an abbreviated request for a booty call. "You can preoccupy yourself with all these things, but at the end of the day, you're trying to figure out how you feel," Danielle Haim told Entertainment Weekly.
• The song was recorded at Los Angeles' legendary Vox Studios and was co-produced by Rostam Batmanglij, formerly of Vampire Weekend. Danielle Haim recalled to Pitchfork:
  
  "The drums were literally recorded with one mic on the opposite side of the room. Rostam is so awesome in the studio. He's like our cheerleader. He was just playing some chords, and this song came out. He was like, 'At the chorus, sing the highest note you can sing! Keep going! Higher!'"
  
  "We don't really write with a lot of other people, but we love writing with him," she added. "When it's just the three of us, we can be like, 'This sucks! I don't know about that line!' But with Rostam, he records everything. I'll sing the weirdest little [half-hearted] 'nah nah nah nah,' and he'll be like, 'That's amazing! That's the chorus.' And we're like, 'Really?'"
• Danielle Haim told NPR the story of the song:
  
  "This one started off with the music first. We wrote it with Rostam [Batmanglij], who also produced it. He just started playing these simple piano chords reminiscent of '50s, early rock 'n' roll.
  
  The melody just came out real quick — it was the first thing that came out of our mouths. Rostam has this awesome ability for coaxing something out of you, he's a huge cheerleader when we're writing. It's different with every song, but with Rostam we'll just start with stream-of-consciousness and record everything.
  
  With the advent of GarageBand, we started writing a lot faster six or seven years ago. You can really just mess around, and it's very easy to go back and hear what you did. It's an easier way to capture ideas."