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.
You don't need to hide your feelings.
ليس عليكِ إخفاء مشاعرك
Du musst deine Gefühle
nicht verstecken.
Ya deja de fingir.
Fais pas ta timide.
Non c'è bisogno di mettere su 
quella maschera.
Não precisa esconder
 os seus sentimentos.