When should I text him?

So I know this guy from the gym and we chilled last Tuesday. We went to the bar, had a couple of drinks (he bought) and we went back to his car and had sex. I remember at the bar we were talking and we instantly hit it off. Non stop talking the entire time we were together. I don’t want anything serious and I know he doesnt either. It was casual. He was saying that we should do this again another day. We still snapchat but we have not talked about the night ever since we went out. I had fun and he had fun too. My question is how long do I wait to contact him again? Or should he do it?