These 2 ladies are most paired together because of their close couple-like relationship and loving heart-felt moments. In most fanfics, Minami would play the male and Atsuko would be the female.
Search Atsumina on YouTube, Tumblr, & etc. and you'll see what I'm sayin'.
Girl2: Oh yeah, dude they are totally gay for each other.
Girl3: God bless Mariko-sama for blogging Atsumina <3