That's typical introversion! When u meet in person you still do wanna make deep conversations but you are afraid you might not be competent and expressive enough to come up with the ideas on the spot sometimes, esp if you havent done it before! So instead of making those interesting comvos he fills the gap with jokes and teasings. The problem isnt that he cant make those convos, he can but he is not sure. So next time you wanna do it, explicitly tell him you wnana make deep convos or ask him thi