How do I tell my man I got off thinking about him?

So I'm seeing this guy and I've sent him some sexy photos for him to get off to but so far we haven't done anything in person. But the other day I got home from college early and got high and masturbated while thinking about him and had the best orgasm I've ever had, like my legs were shaking afterwards and I could barely walk. Now I just want some advice on how to tell him about it?