your school was having a "candy cane mail" for Christmas, and Xiao got you a candy cane. Obviously, because he was your best friend. You could leave a note for the person that receives the candy cane and when you read Xiao's note, it couldn't have been more obvious that it was him who wrote.. he wrote 'make an arrow with it and shove it up your a-'. You looked behind you and saw him giggling as he said in a playful tone

"Well? Have fun eating that candy cane"