Sia revealed she hit up her LSD collaborator Diplo for some casual sex.“Much of our relationship is just being spent trying not to have sex so that we wouldn’t ruin our business relationship because he’s super-duper hot,” Sia recently told GQ for a feature on Diplo.“This year I wrote him a text, and I said, ‘Hey, listen, you’re like one of five people that I’m sexually attracted to, and now that I’ve decided to be single for the rest of my life and I just adopted a son, I don’t have time for a relationship .… If you’re interested in some no-strings sex, then hit me up.’”Sia, 44, didn’t reveal whether Diplo, 41, took her up on the offer.The “Chandelier” singer added that Diplo is “the sweetest thing in the world” but “one of the most insecure boys I’ve ever met.” She clarified that he isn’t insecure with his music but more with himself and his personal relationships.“He doesn’t think that he’s good enough at anything. He has crazy low self-esteem,” she said. “It’s so interesting because he’s one of the most talented and attractive people in the world. But he doesn’t know it.”This may be why Diplo says he doesn’t “really believe” in marriage.However, the Grammy winner is more than happy with his two kids with ex-girlfriend Kathryn Lockhard: Lockett, 10, and Lazer, 6.“I think I found true love with my kids. I get lonely sometimes, I might have bouts of depression. But my kids, they love me. And they can’t escape me,” he told the magazine. “Any girlfriend would end up breaking up with me because I’m so busy, and I’m just a bad boyfriend. My kids, they literally can’t. My job is to be good to them.”And it wasn’t until his former flame of five years, M.I.A., got pregnant with another man’s child that he even considered having children.“My ex-girlfriend got pregnant with somebody else and I was like, ‘Damn,’ because we had almost had a baby together,” he said of his “Paper Planes” collaborator. “She had a baby immediately, and I was like, ‘What the f–k?’”He added, “I kind of lost all hope in that relationship. And then I had a kid, probably like a year after that, because I was just like, ‘F–k it, I want a kid.’”Meanwhile, Diplo was spotted getting flirty with EMD star Chantel Jeffries in early January.