Don't remember what ? Orion saying he's never been with a girl ? I've read it in the script, end of 0.3, the scene with Nancy in the roman bathroom when she asks him if he's been with a girl. If you haven't had sex with Eva or Maat he just says he's never been with a girl, and I assume he's not lying since he's alone with Nancy at this time, and has no reason to lie. Also if you've been with Eva OR Maat, he says "I have once" and if you've been with both he says "a couple of times".
I don't really know what you mean by "more explicit" though, virgin or not it's not like something you yell to anyone every chance you get. Nancy just asks him and he answers truthfully.
As for OIAL I don't remember either. I've wanted to replay it for a while anyway, and with pregnancy ON this time. Though it could take a while, this conversation will probably have moved on by then. So if no one else can confirm for now we're just in this unending loop of us not remembering if OIAL's MC is a virgin or not at the beginning of the game