I've had to get used to my ISTP friend's need to disappear into the woodwork for days at a time, but it's starting to wear on me. His introversion DRIVES ME INSANE.

We have so much fun when we hang out--I love how his mind works. I've even accepted the fact that he answers all my questions with questions. But after a day of hanging out, I want to rehash how very fun indeed the fun was, but he just curls up into his little introverted cave and I don't hear from him for days, which feel like eternities. What's an ENFP to do?