If you make things really easy for a guy, you’re never going to know if you’re with someone who really cares about you, or if he’s with you because he’s too lazy or apathetic to seek a mate. Better to be alone than in a relationship like that.
He has to learn that if he doesn’t ask you out when he sees you he might not reach you on the phone so soon and not see you for a week or two. It’s not that you’re impossible to get, you’re just hard to get. Remember, you’re very busy with activities and other dates and you make plans ahead of time. But don’t reprimand him for not calling sooner by saying, “If you had called earlier…” Just say, “Really, I’d love to, but I can’t”.
(He’ll figure out he’ll have to call sooner.)
You’re not supposed to call men after dates that went well, either. Don’t call “just to see how he’s doing” or with some other silly excuse. If he likes you, he’ll call again for a date. If not, his loss.