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.
So I got cocky.
لذا اعتراني الغرور
Also wurde ich übermütig …
Por tanto me dejé llevar y 
te lastimé con mis palabras.
Je me suis cru tout permis…
E così, sono diventata arrogante...
aí fiquei toda metida.