I haven't gone into explicit detail with my son, but we did have a talk about Internet pornography, as I'm so worried that he'll see some and think that is how sex is supposed to be. Our net filters are as strong as they can be, and I closely monitor his Internet usage, but I have no doubt that pretty soon other boys at school will be showing him things on their phones.
I just told him that pornography is not representative of how people have sex in real life, and that the women in pornography are getting no pleasure from the things that are being done to them, and are often probably in quite a lot of pain. I told him that sex should be gentle and loving and about making your partner feel good. I've also spoken to him about trust and respect.
I think you've been really open with him and that's great. Most kids do know that porn is not normal sex. I joked about it a bit with my lad. I didn't tease him just comments like - good luck getting in the position. You'd need to be double jointed. Having a laugh made it easier for my boy to talk to me. If kids are from a family where they are loved. They see normal amounts of arguments. That parents are civil and show respect to each other whether they are together or apart. Your child is v likely to enter into good relationships when older. He'll be fine.