A pairing withing the Kingdom Hearts fandom containing the characters Zexion and Demyx. It is commonly used to decifer who is on top in this relationship, there being the fangirls who like Zexion as seme or Demyx, Usually the person who's name comes first is on top, as opposed to Zemyx, where Zexion is on top.
Fangirls1: Demyx is a awesome seme(top)! Zexion's the cutest uke!(bottom) Dexion is win!