It might not be how it was supposed to go for either of them (Mami expected candle lit dinners, romantic walks on a bridge in winter holding hands and standing together to keep themselves warm) but it was how it was. Mami had feelings for Rin, as silly and awkward as she could be, but had kept them hidden, because she couldn't let herself love someone else, not while she had to deal with witches. How could she fall in love with someone if she couldn't be 100% truthful? And then finding out Rin knew magic too, that she could finally stop lying to the other girl..

"But you want to know that the girl you like cares about you, don't you?" Mami gladly let Rin against her chest (it probably wasn't the first time she'd done that either, though definitely the first time naked.) holding her close. "Tohsaka-san is the prettiest girl I know, it doesn't matter if your breasts are small."