Never shower him with excessive affection and attention because this will create a counter effect from what you want.
In order to be a challenge, you have to give him everything bit by bit.
This means you should never tell him everything about you instantly. Give some of your info to him, and keep the rest for some other occasion.
This also applies to physical contact. Always give him a little bit, and make him thirsty for more.
These mysterious scenarios will create an intense attraction in him, and he will appreciate everything you give him, hoping that you’ll come back and give him more of what you’ve got.