Corey Taylor may not be able to entirely mask the pain he still feels from his "unplanned spinal surgery" in early June under his Slipknot character visage. But the silver lining is that he's been a better vocalist during the group's summer tour with Marilyn Manson.

"I've been damn near on, pitchwise," Taylor tells Billboard. "My stamina's a lot better. It's like I'm really kind of filling in all these weird blanks in [the music] I never even realized were there. I love the challenge of it. It's being able to tune in even more to the music, really kind of being IN it, more than I ever was before." The injury has also made Taylor more aware of the particulars of his manic performances.

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"I've had to kind of reassess what I do live," he explains. "Up to this point I didn't realize how physical I am when I sing -- even more than just headbanging or jumping or running or any of that stuff. I punctuate physically when I sing, and I never realized that before. Even the first few shows I was finding I had to hold myself back from more than just the headbanging, y'know? I would do something and it would be like, 'OK, that hurts. OK, we can't do that for awhile.' I've had to reassess what I do live. But the positive for me is I love the challenge of it. I love the fact that it's like, 'Well, OK, maybe I've relied on those things for too long. Let's see if I can get through a show or a tour without having to go to these kind of mainstays,' and the shows have been great, so it's working."

Slipknot will be on the road through its annual Knotfest on Sept. 25. This year, Knotfest shares the weekend with Ozzy Osbourne's Ozzfest -- which helped Slipknot achieve liftoff as a buzzed-about second stage act in 1999. "I think it's gonna be great, man," Taylor says. "It's kind of a lot of things for us. It's us really trying to solidify our brand while also paying respect to the brand that not only kind of started it all but also helped us get to where we eventually got to go. Every time we were part of Ozzfest we were treated like family, and we did everything we could really to go above and beyond for them because they treated us so well. For us to be able to partner with Ozzfest and really be able to make something incredible, to me it's just about respect and saying 'thank you' -- and also doing something killer for the fans."

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Once Slipknot's touring wraps up, the group is looking at going into dry dock again, though likely not for as long as the six-year interim before 2014's .5: The Gray Chapter. Taylor is looking at a couple of years back with Stone Sour. The group has written and demoed 18 songs for its sixth studio album, with plans to hit the studio this fall for a likely 2017 release.

"It's some of the best shit we've ever written," Taylor says. "I'm champing at the bit to record it and get it ready to go. The cool thing is that it's got a lot of different directions, but at it's core it's very hard rock, and I mean that in an almost sort of modern/classic sense. There are some hints of punk in there. There's some cool hard rock/heavy metal. There's just all these really cool elements that we've never really allowed ourselves to go into. We're really to kind of push even further with this. It'll feel like it's all over the map, but it will be very unifying when everyone hears it. It's exciting, man."

Before that, Taylor will be heard as a guest on a track for Korn's new album, The Serenity of Suffering, which comes out Oct. 21. "That was really cool. I didn't even honestly expect the call," Taylor says. "I knew they were working with Nick [Raskulinecz] and Nick hit me up and was like, 'Dude, this fuckin' shit's going really well...We've got this tune, we're trying to wrap our head around it but it might need you. I was like, 'Fuckin' when do you need me? I'm getting on a plane.' I literally booked the flight the next day and flew down and did it. I just belted it out and we just kind of went for it. It was cool." He also got an earful of the rest of the album. "It's was fuckin' balls-out, man. It was like this old school kind of Korn vibe to it, from the first two albums that I absolutely loved. I can't wait for people to hear this. It's some of the best shit that they've written in years. It is so good people are gonna lose their fucking minds."

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Also on Taylor's docket is his next book, another essay collection tentatively titled America 51. He's been watching the presidential campaign as well as the recent police shooting incidents, so he expects the book will have plenty of socio-political spleen-venting. "Y'know the more I watch and the more I read what people say and think, it's like how far off the mark was I on where this country was?'" Taylor says. "And I don't know if that makes me angry at them or angry at myself, but it's certainly a mindfuck. The book'll be out next year; I'm still really in the baby stages of it, just getting stuff together. And I've been so busy with Slipknot and then the surgery really kind of threw me for a loop. Hopefully I'll be able to get it out by next year and that'll give me something to write about all through the election. It'll almost be a post-election kind of vibe."