It could be from any manga or anime ;3
For me...
Sebastian and Ciel from Kuroshitsuji
(8059) Takeshi and Hayato from KHR
Sasuke and Naruto from Naruto: Shipuuden
(D1 cool Dino and Hibari from KHR
Shizuo and Izaya from Durarara!!
Germany and Italy from Hetalia
Spain and Romano from Hetalia
Russia and China from Hetalia
America and England from Hetalia
Sweden and Finland from Hetalia
Greece and Japan from Hetalia
Lithuania and Poland from Hetalia
(Aaaaah~ <3 Sooo many Hetalia characters :"3)
......
Haaaaa.. >:3 and soooo much more...
Who's yours? :3