That's only if the person has been good to you, of course. You don't owe anything to anyone, but as long as your casual sex buddy wasn't physically or emotionally abusive, then it's nicer to explain why you want the sex to end. "Even if you had a one-night stand, send a quick text to say, 'Hey, I had fun last night. Good luck with everything,'" Lilla says. If the relationship was longer (like several months to several years), she suggests a face-to-face convo (yes, even though it's hard to reject someone to their face). Take your sex buddy to a public place, like a coffee shop or to lunch, and tell them that you want to stop seeing each other. It's easier than your place or their place because it's less likely that they'll "cause a scene," Lilla says.