According to the fans, Homu x Homu is the new world.
That goes without saying, HomuxHomu is a tag originated from the couple Homura Akemi and Homura Akemi in the anime series, Puella Magi Madoka Magica.
Illustrations of this pairing surfaced right after the TV broadcast of episode 10. With the appearance of glasses Homura, artists started to pair the Homura of the past with Homura of the present, thus formed this pairing within a day.
Even though it's obvious that combining short form of two names without applying "x" automatically denotes the coupling itself, since the term HomuHomu itself is a nickname of Homura, fans of the show attached an extra x to prevent any unwanted confusions about the term.
Interestingly, it is also possible to form a triple pairing HomuMadoHomu considering the drastic difference between the past and the present Homura.
|↓Denotes／Opponent→||Madoka Kaname||Kyouko Sakura||Mami Tomoe||Sayaka Miki||Homura Akemi|
|When Seme||HomuMado（Black Knight and Pink Princess）||HomuAn||HomuMami||HomuSaya||Homu×Homu|
|When Uke||MadoHomu（You are my best friend）||KyouHomu||MamiHomu||BlueHomu||(HomuxHomu）|