Songfacts®:

• Troye Sivan wrote this with regular collaborators Bram Inscore, Brett McLaughlin and Allie X. The YouTube personality explained the story of the song in a Genius annotation:
  
  "I was sitting in the writing room with Allie X before we started writing this song and she was in her Tumblr inbox. There was a message from a fan that said 'Allie X my youth is yours' and I was just like oh my God that is so poetic and awesome and such a cool way to say 'I'm experiencing my youth to your music.'
  
  It just hit me in so many different contexts. If you get into a relationship when you're young with someone you're giving them your young years you're giving them your youth. But also from my perspective a little bit I felt like it meant something to me with my audience, having been online since I was 12 I feel like I really have given a lot of my youth to a lot of people. So it just kind of hit me in all these different ways and then we started writing the song."
  
• Not everyone is in the public eye like Sivan and this song evolved into a concept that people can more readily identify with. "The idea of getting into a relationship when you're young, and waking up when you're 25, and you've given all of your young years to a particular person, that was super romantic and cool to me," he explained to Radio.com. "And we started writing a song about leaving everything and running away and having absolutely no idea where you were going, or what you were going to do in the future, or whether this person is just going to be with you for two days and just be a fling, or is it going to be someone who you are going to spend the rest of your life with. And having all of those questions and still not caring about any of the answers because you're young and you don't have any responsibilities."
• Sivan was the musical guest on the December 8, 2015 episode of The Tonight Show Starring Jimmy Fallon, where he performed this song accompanied by the Roots. It was the Australian singer-songwriter's first ever US TV appearance.
• The song's music video was directed by Malia James and shows a slightly bizarre house party. "Every room has a different sort of trippy thing happening," explained the director. "We just wanted it to capture all of the best parts of being young and having fun."
  
  Actresses Amandla Stenberg and Lia Marie Johnson appear in the clip.
• Fun Fact: The silver jacket that Troye wears in the video actually belongs to Malia James' father.