I do not have casual sex without a condom.
Once, unbeknownst to me, a playmate removed his condom during a position change. I assume that's what he did. I put a condom on him myself. I knew when it felt different. I asked him to check, and he pulled out and reassured me. It was absolutely dark, and I took him at his word. But he lied. He ejaculated inside me. I had already decided not to see him again. Intercourse was painful, and he seemed unconcerned. Like the pain was normal. It didn't have to be. So I was going to just tell him it was over the next time he asked to see me. But then I smelled the semen as I drove home. So, I called him, and challenged him on the condom. He swore everything was fine, that he wore it, came in it, threw it out. But I got home, and found semen in my panties. I inserted my fingers into myself, and pulled out more.
The rest of the story doesn't matter, other than he tried to stalk me, and failed, and he harrassed me by phone for a while. He also messaged me a year later on a dating site, and asked me for a ride to work. Obviously, he was mentally impaired, and I hadn't caught it until it was too late. Luckily, I didn't catch anything else, either.
I know how to find him, he can't find me unless I want him to. He doesn't know my address nor my name. New men get only a nickname and a partial last name, and a Google voice number. If they turn out to be crazy...
Anyway, that's the only time, really.
Once, when I was very young, maybe 19, with an inexperienced boyfriend, he came a little inside me. He was supposed to pull out. He did, but he immediately confessed that some had come out unexpectedly before he removed himself. I believe it was an accident. He was remorseful. There was a week every month where he was allowed to inseminate me. He only messed up the one time. I was worried, not angry.