The term Host-Hopping disease is an Ouran Host Club invention, which the Hitachiin twins also call the Never-the-same-boy-twice disease and which the manga calls the Fickle Female disease. The affliction refers to Host Club guests who tend to change their minds about choosing their favorite Host is on a regular basis, thus "hopping" from boy to boy seeking resolution to their dissatisfaction. Typically, guests choose a single Host who they visit and chat with as their "favorite;" Tamaki Suoh having the most followers.
The guest who has been openly deemed to have the "disease" is Kanako Kasugazaki, though it's not not revealed how many Hosts have been her favorite since coming to Club, nor in what order. It is known that her most recent choice is Tamaki, the "King" of the club with a 70% request rate. In Ep 02 - The Job of a High School Host! Kanako meets Haruhi Fujioka and changes her mind yet again to "hop" from Tamaki to the "natural" Host and Club rookie. Her Host-hopping days end when the Host Club intervenes and helps her reunite with her childhood friend and current fiancé, Toru Suzushima. Yet, even after Toru leaves to study abroad to better himself for Kanako's sake, she continues to visit the Host Club from time to time.