Just explain that to him. Tell him you aren't ready just yet and you'd like to take a step back. If he doesn't like that, then that's on him.

By the excellent answers below the key point is communication...

In the end communication is probably one of the most important aspects of human relations

I have few regrets, those I have had I probably would communicate better if I was back at that point again...

Talk to him about it. That's also a good way to test the waters and see if he's ready for a relationship. I think that if he can't talk about important stuff like that now, he won't be able to when it really counts. Share your feelings with each other.

Set boundaries, talk it out. "You're awesome and I'm really concerned about rushing too fast and ruining this. To make it work I need to take a step back." Or something like that.

Be honest with him.

Talk to him about it...

Explain it to him

Tell him that you are not into sausage 😄

idk, i never fucked any guy before