Spoilers ahead for the entire third season of Stranger Things.

When Stranger Things’ second season first introduced us to Max (Sadie Sink), our fiery tomboy from California wasn’t taking shit from any of those Hawkins boys: She whooped their asses in the arcade, taunted them with her sweet skateboard moves, and, on occasion, would even write them notes reminding them of their creeper status. Thanks to her natural love of adventure and penchant for paranormal kickassery, though, Max soon became an integral member of the gang, a dynamic that changes further in Stranger Things 3when she befriends Eleven (Millie Bobby Brown), leaving the bad vibes between them in the past.

Essentially appointing herself as El’s love guru, Max bestows her friend with round (“boyfriends lie, all the time”) after round (“you’re going to treat him like garbage”) after round (“dump his ass!”) of dating advice, in between giving each other mall makeovers and lusting over Ralph Macchio centerfolds during sleepovers. What do you know — girls just wanna have fun, even when the Mind Flayer and his army of human hosts come to town! Feeling inspired by this delightful surprise of Max and El becoming pals, Vulture called Sink earlier this week to discuss how her actual friendship with Brown helped map out the season, the joys of filming that makeover, and how she wants to see Max’s story unfold going forward. (RIP Billy.)

How does it feel to have inspired countless women with your “dump his ass!” quote?
It’s great. I remember when I first read that scene in the script, I was like, Okay, this is gonna be iconic. Dump! His! Ass!

This was the scariest season for me to watch, so I loved all of those friendship scenes between you and Millie. But before we talk about that, were you bummed you didn’t get to do a lot of skateboarding? You trained so much for it!
I think I had too many skateboarding scenes last season. I was always so worried and hoped I was doing well when we filmed those scenes, since the show gave me so much training. I would always think, What if I wasn’t doing the best I could? So, I didn’t mind it too much. Also because, during the hiatus between seasons, I definitely didn’t do as much skateboarding as I should have. My skills were way rusty.

How did your actual friendship with Millie inspire your characters’ dynamic? Did you two give the Duffers ideas for your bonding scenes?
Millie definitely made it known to the Duffers that she wanted our characters to be friends. I did, too, but she was much more vocal about it. That was exactly what she wanted. At the end of season two, you see the one interaction El and Max had, and it was set up in a way where they were being pitted against each other — which is a direction too many TV shows and films go in. Like, they always want to put two girls against each other and have a lot of jealousy between them. I’m so glad the Duffers did the opposite and had us become this iconic, powerful duo. Millie and I are such good friends and hang out so much off set, we figured, why not spend more time with each other on set, too? Because we have that genuine bond, it helps with the chemistry in the show.

Despite you two being the only girls in the friend group, as you said, your characters weren’t particularly close last season due to that jealousy element. Boy problems aside, what do you think motivated El to finally reach out to Max for some one-on-one time?
Eleven is such a powerful character, but not in the way that Max is. El is powerful in the sense of the supernatural and the superhero, but when it comes to communication and confidence skills, it’s not there for her yet. But with Max, she’s unapologetically herself and she’s so comfortable with who she is. I think Eleven saw that in Max and that’s why she reached out to her. They can both learn from each other, too.

What have they learned from each other?
For El, it’s definitely having that confidence and coming into herself. Not being influenced by everyone else in her life — like having Hopper and Mike being such an imposing presence over her. She’s becoming her own person. For Max, it’s good for her to have a friend like El who she can teach, street smarts or otherwise. She had trouble being accepted by the group and El at first. It was such a big moment for Max to share a bond with another girl, which isn’t something she’s necessarily used to. I bet she’s used to people not liking her at first.

I loved the makeover montage in the mall, since it was a rare moment when the girls weren’t preoccupied with the Mind Flayer. What was it like to explore that massive set and pop into all of the stores? Was it as fun to shoot as it looked?
There were a lot of revisions for that montage! They had all these different activities planned, and Millie and I got to pick and choose what we were doing, which is what you end up seeing. At one point, we were going to get our ears pierced and have a feast in the food court. It was so fun. It took two days to film that montage. It was really great to let loose and not be fighting back tears or being terrified for once. You need to be silly sometimes.

Were you two able to get your ears pierced anyway?
We didn’t shoot that, unfortunately. And it was the one big activity we were excited to shoot! I don’t have any piercings in my ears, so we were discussing actually having my ears pierced on camera, but we ran out of time. I still don’t have my ears pierced!

Did you wind up snatching anything from the stores as a souvenir?
That mall was huge, it’s still nuts when I think about how big it was. When I first stepped onto that set I truly couldn’t believe it. At the end of shooting, a few people went on some shopping sprees. Millie grabbed a shopping bag and went around the Gap and got a bunch of stuff. I picked out a few clothes, but I accidentally left them in my trailer and they never made it home. Every single store was decked out with things that would actually be in that store in 1985. Wicks ‘N’ Sticks had about 1,000 old-school candles. My favorite place was the shoe store, where El tried to walk in heels and fell. It had all of these crazy vintage shoes, like sneakers that are worth thousands of dollars now. We were given strict instructions, Do not touch the Nikes! These are on loan!

What did you and Millie like to do together when you weren’t filming? I imagine eight months in Atlanta gives you lots of time to kill.
We’d  always have sleepovers. We’d alternate between houses, but sometimes I’d drag her over to my house when I was being lazy. Our houses were on a lake, so I forced her to go canoeing with me, which didn’t end well. [Laughs.] In Atlanta, there’s a place called Ponce City Market, which is kind of like Chelsea Market. I brought her there once, and we did those Bird scooters. They’re very dangerous but fun! We only did them on the BeltLine, so there were no cars, thankfully.

Moving on to another character dynamic of yours, how do you think Max mourned Billy during the three-month time-jump? They definitely had a contentious relationship, but were still step-siblings who showed affection to each other in their own ways.
It was interesting, because when I first read that script and saw how it outlined the time-jump, I was like, Wait, why is she so happy? That was an upsetting death! The first time you see Max after that tragic scene is her smiling and singing with Lucas. I feel like she’s very conflicted and had been the entire season. She and Billy didn’t have a great relationship and never had, but in the end, he’s still her brother and they do care for each other. We don’t really get to see a lot of that mourning process she goes through, just that glimpse of her looking into his room. But you can tell she’s affected by it. She’s tough and puts up walls. She’s trying not to show that with others, I think. I’m interested in seeing how that progresses.

That scene you two shared in the sauna gave me pause when I first watched it, thinking about their relationship. Have you thought about why Billy, while possessed as the Mind Flayer, was willing to terrorize and physically harm Max, but not somebody like Mrs. Wheeler?
I’ve been thinking about that a lot. I think it comes down to the power the Mind Flayer had over him had reached a point beyond return at that point. When he’s with Mrs. Wheeler in the pool, he doesn’t necessarily attack her because he still has some control over himself. But slowly it starts to increase, and when he sees Max in the sauna, that’s when he snaps and fully becomes possessed. From that moment on, you don’t see Billy ever again, really, until his final sacrifice.

I talked to Dacre about what it was like to film all of his incredibly intense and exhausting scenes, which he described as the acting challenge of a lifetime. Looking back, which of your scenes gave you the biggest difficulties as an actor?
Every scene is difficult in its own way, but the big scenes for me were the sauna and Billy’s sacrifice in the mall. With the sauna, it’s always unsettling to see your friend — and Dacre has become such a good friend — fully in monster mode. He’s such a good actor and is so believable, so it’s always an initial shock when we begin filming. But it’s also a double-edged sword: For that end scene in the mall, when I’m watching him sacrifice himself and get attacked with tentacles, he’s not really there. I wasn’t actually watching him, it was either his stunt double or something even worse, which was a beach ball on a stick. That’s what I watched when I “watched” him die. [Laughs.] It was a massive beach ball! One of our assistant directors was shaking it back and forth. I truly had no idea what I was doing, I just knew I had to be traumatized. But once I actually sit beside him in the end, when he dies, I was able to be with Dacre and have that beautiful exchange.

What do you think will come next for Max in season four? Will she ever dump Lucas’s ass?
She already dumped his ass five times!

I should say officially dump his ass.
I don’t know if she’s ever gonna follow through with that. [Laughs.] I’d love to see where Max is at, mentally and emotionally, after Billy’s death. They didn’t have the best relationship, but his passing dramatically changes the dynamic within her family. I want to see how she copes with that. If there’s another season, the group will also be in high school at that point. It’ll be interesting to see what trouble they’ll get into while growing up.

If there’s anything worse than middle school, it’s high school.
Oh, don’t even get me started. It’s a whole other beast.

Stranger Things’ Sadie Sink on Max and El as an ‘Iconic Duo’