Songfacts®:

• The titular walls have two different meanings here. The sugar walls are a vagina euphemism (previously used by Prince for a song he penned for Sheena Easton) and Lamar offers various sexual innuendoes where he is enjoying himself physically with a woman. There are also real walls, which are obstacles to the woman.
  
  Her lover is the same man that killed K-Dot's homie, Dave, whom he rapped about on "Sing About Me, I'm Dying of Thirst." The woman's lover is serving a life sentence, and she eases her pain at the separation by having sex with a famous rapper – one Kendrick Lamar.
• Lamar receives vocal assistance from neo soul singer Bilal and Sonnymoon's Anna Wise on the track.
  
  Wise previously sang on Lamar's good kid, m.A.A.d city track "Real" and is also featured on "Institutionalized."
  
  K-Dot originally discovered Wise on the internet through a YouTube video of the Sonnymoon song "Nursery Boy." She was on a road trip with her bandmate Dane Orr when the Compton rapper first contacted her in 2011. Wise recalled to Billboard magazine: "We were texting back and forth, and then we just decided to reroute our road trip down to Compton. Dane and I showed up maybe like a week later, and we lived there in the houses they had set up at the time, the recording studio - we just stayed there and we worked for like, many, many weeks in a row. It was really cool."
  
  As soon as we entered the room," she added, "we just knew that it was going to work out between us creatively - like love at first sight, but creatively."
• Bilal, who contributed to six different To Pimp a Butterfly tracks, told Billboard about his creative process with Lamar. "A lot of this is Kendrick's genius," he said. "He kept speaking about having a big sound, a Parliament type of thing. And I'm all about that because George Clinton is my favorite artist. For a lot of the material, Kendrick had a sketch idea of what he wanted. He would sing out the melody and some of the words, and I would just interpret what he was telling me. On the songs where I added backing vocals, some of it was freestyle; just adding color to make it a fuller sound."
• Kendrick Lamar closes the song by referencing a meltdown:
  
  Resentment that turned into a deep depression
  Found myself screaming in a hotel room
  
  Lamar told The Guardian that was a real incident in (he thinks) an Atlanta hotel, in December 2013, during his tour with Kanye West.
  
  Asked what made him scream, Lamar replied: "It was something that just accumulated. You know when you get bad news after bad news after bad news? And you can't express this to nobody but you got to relieve it in some type of way? I was able to bottle that moment and put in on record."
• The explicit Colin Tilley and the Little Homies-directed video is labeled a "black comedy" by the beginning title sequence.
  
  It starts off with Moochie (played by comedian Corey Holcomb) sitting in a jail cell explaining how he found himself in prison. According to the inmate's story, it's all Kendrick Lamar's fault.
  
  Moochie proceeds to go deeper into the tale, which progresses to a crazy house party filled with dancing girls in a debauched motel. Later there's a talent show in which Lamar and actor Terry Crews (Everybody Hates Chris, Brooklyn Nine-Nine) dance to "Hit the Quan." The clip concludes with a "To be continued…" tag.
  
  Asked by Billboard magazine if he and Lamar had to choreograph their dance performance, Terry Crews replied: "All of the stuff was ad-libbed when we were doing the [scene] in the car and I just got pumped. This took me back to my days in [my hometown] Flint, Michigan, and what was going on. I think it's good for me a lot of times to do that stuff because it was one of those things [where] they let me just roll. So a lot of that was improvised but we spent some time, practicing the Quan."
  
  "I had a video of the Quan and we went through it a little bit. We did it about 10 times and made sure it got better every time. We kept practicing it and it kept getting more and more intense. It's weird because it kinda had a life of its own. We didn't even know what we were doing at one point. It just became what it became."
  
  
  
• This won the Grammy Award for Best Rap/Sung Collaboration at the 2016 ceremony. It was one of five awards Lamar won that year.