Ian doesn't like the feeling of being touched, but he enjoys every touch you give him. Every time you touch him, hug him, and kiss him, he likes it but he doesn't show it and acts normal as if nothing happened.

that's why you like to tease him, and your teasing sometimes makes him unable to control his lust for you.

"Stop teasing me before I really eat you." he said, holding back a groan when you deliberately teased him by sitting on his lap while kissing his neck.