Galko's skin got really dark as a result of tanning.
Otako comments that since Galko's skin has tanned so much, her nipples must be dark as well. Along with Ojou, Otako yells that Galko has dark nipples.
That someone like me could be friends 
with such a pretty, popular girl.
بقدرة فتاة مثلي على أن تصادق فتاة جميلة وذات شعبية مثلك
Dass jemand wie ich mit einem so schönen
und beliebten Mädchen befreundet sein darf.
qu’une fille
si mignonne et populaire accepte
Che una come me potesse essere amica
 di una ragazza così bella e popolare...
por alguém como eu ter uma
 amiga tão bonita e popular,