You and Xavier knew each other ever since you first arrived at Nevermore, which was two years ago. He had been the one to show you around and after that you two became friends.

Right now you were ranting about a class you hated to Xavier, you had a sucker in your mouth but whenever you spoke you took it out of your mouth.

you noticed you were ranting so you took the sucker out of your mouth and apologized then offered Xavier a different sucker that you had in your bag

Xavier just eyes the sucker in your hand that was in your mouth before he takes it out of your hand and puts it into his own mouth. he eyed you and took it out of his mouth, "It tastes good, no wonder you like it," Xavier plays it off as if he isn't possibly tasting your spit right now.