On Saturday, the National will become the first band to headline Latitude twice. “Some festivals you have a warm feeling about, and others, a shiver goes down your spine when you hear the name,” says their lanky frontman, Matt Berninger. “With Latitude, it’s definitely the warm feeling.” The Cincinnati band first played the festival in 2007, reappeared in 2010 and took their first headline slot there in 2011. Nipping at their heels are Chvrches, who have leapt up to second on the bill after first appearing in a tiny tent in 2013, three months before releasing their debut album.

Not that there is any competition afoot. Last October, Chvrches’ frontwoman Lauren Mayberry joined the National onstage at San Francisco’s Treasure Island festival to sing I Need My Girl, and the bands have developed a bit of a mutual appreciation society. We got Mayberry and Berninger on to a conference call to discuss the possibility of reprising their collaboration, what it’s like becoming comfortable onstage as introverts, and how festivals help bands survive in 2016.

Watch the National perform I Need My Girl with Lauren Mayberry

Do you enjoy festivals?

Lauren Mayberry: It’s always quite fun, because we get to experience a lot of different communities.

Matt Berninger: I used to be overwhelmed by festivals. I never went to any when I was young – even school fundraising carnivals. I didn’t like the crowds. I’m uncomfortable in that chaos of people, and so festivals induced higher levels of anxiety and homesickness. But now I love it. I’ve learned to roll with all the chaos.

It probably helps that you get much nicer facilities as a headliner.

MB: I’m sure that’s part of it. It’s nicer when we have four trailers, a lawn, your own little dreamzone.

Is there a big culture difference between British and American festivals?

LM: I think, with British festivals, there’s a bit more of a grin-and-bear-it approach but, weirdly, more of a sense of reckless abandon also.

MB: Definitely. I think the UK is a different level of chaos. I never get groped anywhere else. There is a distinctively British festival mindset, which is all its own, and both terrifying and exhilarating.

What would it take for you to get out into the crowd and spend four days in the mud? Would the Smiths have to reunite for you to do it, Matt?

MB: [whistles] Before, I would have said I would need a popemobile bubble, a cone of silence, and my own Portaloo at all times. If the Smiths got together, yeah, I think I would do it.

Chvrches: in their early days, the band nearly missed their first festival gig

Lauren, do you ever do them as a punter?

LM: I haven’t for a long time, but I feel like if you had the right group of people, then maybe it could be OK [sounds sceptical]. I can’t see myself doing it in the near future.

How were your first band experiences at festivals?

MB: Our first significant festival, the whole reason we could afford to fly over to Europe was because we got this one festival gig that paid more than all of the other shows on the tour put together. We got held at the border and almost missed it. We drove in, moments before we had to take the stage, and Cold War Kids let us use their gear, so we made it. Had we missed it, we would have lost all the money that was supporting the entire tour, and we were at a point where we might have just thrown in the towel. More people are going to festivals, because people have stopped buying music, so they’re really the way that young bands can stay financially above water and keep chasing it. So I am genuinely grateful that so many people want to camp out in the mud to listen to music for four days. It’s why we still exist.

Are you comfortable up there?

LM: Yeah, it was important for us to get there at our own pace. We didn’t really want to do a pantomime version of the performance just so it would seem more exciting to look at. We went from playing small clubs to quite big stages quite quickly and, a lot of the time, I felt like I was trying to catch up with myself. Figuring out how to take up space was an interesting journey.

Matt Berninger and Lauren Mayberry at the Treasure Island festival in October 2015. Could they perform together again? Photograph: Tim Mosenfelder/Getty Images

Would the National have survived if you had started headlining festivals after your second album?

MB: Definitely not. No one would have let us headline a festival after our second album for good reason. I’m really thankful that our evolution was pretty gradual, because I think we might have gone off the rails. Had there not been such deep bonds between us we probably would not have stayed together, even when things were going well. Lauren, you guys seem like you have a very genuine connection, and are protective of each other, and are smart about how you’re doing it. I’m impressed with your ability to evolve so quickly and so gracefully.

LM: I feel like there was a lot of rocking back and forth in the foetal position and trying to figure it out, so as long as that didn’t become clear to anybody then that’s fine.

MB: You gotta learn how to own that foetal position. Curling up in the foetal position onstage during a show when you just can’t deal with it is actually a good time. It’s fun to watch.

Chvrches are on before the National at Latitude. Would you collaborate again?

MB: I don’t know. I would love to. But that is 100% up to Lauren and her gang. Also, I’m not sure if we would add anything to their show. You certainly added a lot to our show when you came on.

LM: Plus we got away with that by the seat of our pants. I’m not sure lightning will strike twice like that.

Matt should come on with Chvrches to do a huge banger.

MB: I could come out and do the Bez thing. Honestly, the times I have been invited to perform on someone else’s thing, it was terrible. I did this charity thing with Arcade Fire where I sang Wake Up. It’s one of my favourite songs and I butchered it. I got nervous and started singing in the wrong key and Win Butler literally had to take the mic away from me. I’m very thankful that he did. I don’t know if Lauren wants me up there ruining her show.

The National performing at Latitude in 2010. Photograph: Andy Sheppard/Redferns

If you could steal a performance move from each other, what would it be?

LM: I really enjoy you invading the crowd with the extra-long mic cable. But I feel like it’s such a unique thing to you that if I stole it, people would know that I stole it.

MB: It’s like my string that I crawl back out of the darkness with. It’s hard to dance and be up there in your own skin and bones and own it and look cool. David Byrne can do these things, and you can do it, Lauren – you just look cool, no matter what you do. I wish I had a little more of that.

Lauren, you listened to High Violet a lot while wringing out mops in a cafe. Is that your main association with the National?

LM: The mop-bucket part is more about the time and place, so that’s what makes it extra nice to be playing before these guys at a festival now, because it makes you remember how far you’ve come in a short space of time.

MB: I’ve got a great idea.

LM: I’ll come on and mop your set? It might be rainy, you might need it.

MB: No, I’ll mop your stage! That’s perfect. We’ll recreate in reverse how you found our band. That’s a great idea. High art. Meta.

Lauren, is there a National song that you want to request?

LM: When you have as many records as the National has, curating that festival set must be quite difficult. We have two albums, so we kind of just play what we think is the best of those two albums.

MB: We are trying to play a lot of new stuff, push the birds out of the nest really early before they can fly, just to see what happens when they hit the ground. That’s a really brutal metaphor. But we’re learning to be less hyper-curatorial about our own sets. I’m much more comfortable falling on my face publicly onstage now than I used to be. I don’t care about humiliating myself. I can’t tell you how much the anxiety of performing has been lifted off my shoulders. I’m enjoying being in a band more than ever right now because of that.

The National and Chvrches appear at Latitude festival in Suffolk on 16 July.