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.
Hey, you know about inverted nipples?
هل تعلمين بأمر الحلمات المقلوبة؟
Hey, mal von Schlupfwarzen gehört?
¿Conocen los pezones invertidos?
Les mamelons inversés…
Ehi, sapete cosa sono i capezzoli introflessi?
Ei, já ouviu falar de mamilos invertidos?