"I'm just trying to be a friend to him," Perry told the magazine. "But it is unfortunate that I do have a set of t***."
The "Teenage Dream" singer went on to say that when rumors that she was dating Pattinson began, she texted Kristen Stewart to set the record straight.
"I sent her a text message saying: 'I know you've seen all this stuff but you know I would never disrespect you. I'm not that person.'"
The 28-year-old singer added that the "proof there was never a anything going on" with her and Pattinson was simple.
“I fart in front of him," Perry said. "Properly fart. And I never, ever fart in front of a man I am dating. That’s a rule. He’s my bud, I’m like his big sister. We just hang out. The other day, I said: ‘One of the things I’m most proud of is not sleeping with you, Robert.’ And that’s true.”
Asked about her recently on-again relationship with John Mayer, the singer explained that it was him who "pulled away" when they broke up and that she made use of her alone time to deal with a few issues of her own.
"That was a big hello for me," she said. "I realized I could lose the person I loved and I had to deal with some things, issues I think a lot of women have. You can be strong in one aspect of your life but submissive in another."