Amongst a herd of tour buses, Sarah Barthel, one half of Phantogram, poses in knee socks and an all-black outfit she's magicked moments before from some FedEx boxes in her dressing room. She and her "son" (dog) Leroy have just arrived in Delaware to play a vibe-y set at Firefly Festival (Barthel, not Leroy), ahead of which she spoke with Marie Claire about the lack of women headlining festivals, constantly reinventing herself à la Bowie, and how Slash influences her hair choices. On the beauty liberties rock stars can take: "I either go because I just sweat it all out. Keep the hair messy because it's just going to get sweaty and disgusting. There's no reason to waste your time on straightening it. Luckily, rock stars can get away with looking disheveled. I really like Milk Makeup—they have really cool, shimmery colors in cool textures you put on your eyelids. BUY IT: Milk Makeup Eye Vinyl, sephora.com. On the loads of different hairstyles she's had (and why she had to cut it all off for her health): "From the beginning, I had black hair, the simple bob with the bangs. I kind of embraced Cleopatra a lot, especially with my accessories and jewelry. Then I grew that out and tried to bleach the tips, but they turned bright orange because they're so damaged. I've been growing my bangs out for 10 years. I always have them, and I just love and hate them so much. Then I chopped that stuff off and started growing my roots out and bleaching them white so I could have white and black. Then it fell out, and my physical therapist also told me I needed to stop head-banging as much because it messed my neck up. So I needed a different kind of vibe and energy on stage, so I decided to cut something different. I'd gotten so used to that being a part of my performance that it's caused some long-term damage, so I have to think about that now. That's when I went short. It's different, it was smart, but it's hard to not head-bang on stage. It's really hard." On which look feels most true to herself: "I think all of them do, and as an artist, it's natural and normal to transition and grow as long as it's organic and real. I was stuck with that bob haircut for way too long. It was one of those things where everyone was pumped to see it go. If I didn't change something, I would have turned out to be Slash. Slash is Slash. I would've had to have the cut forever. I wanted to switch things up and also do things differently on stage." On wishing more dudes would wear makeup: "You know Perfume Genius? I love what he's doing; I think it's so cool. And he pulls it off so well, with the lipstick and the kind of weird cutoff dress. I love that kind of shit, and I also just love the confidence. Performing, I'm inspired by men like Prince and Bowie, where their performance, it didn't matter if they were men or women wearing crazy glam and heels and weird shit and owning it. It's a performance and it's your art, so when guys do it, I love it. I wish they would do it more. I wish it was more of a normal thing. Wouldn't that be cool? Like straight dudes in a four-piece band, let's put some glitter on. I love when people get into what they look like on stage." On being one of the few women on *any* festival lineup this year: "It's kind of always that way. Right now, it's a weird year for festival lineups, and I think everyone maybe had a little realization of like, 'Well, how do they pick these bands and the headliners, because it's always like the three main bands?' For me, it's normal. There are a few , and we all love each other, and we all get together, and we're like 'F*cking yeah!' It's cool to be the only female. Me being a woman is exciting to people, because it's just woman power. I play in a band, and people don't see it as much—they just see pop stars, and if you're female you should be a Taylor Swift or something. But I'm not that, and I don't want to be that. I represent a different part of the music industry, so I'm at festivals with all the dudes while Taylor Swift's at all the arenas playing for kids. It's just different, but we're all doing our thing." Follow Marie Claire on Facebook for the latest celeb news, beauty tips, fascinating reads, livestream video, and more.