I love how Charlie is absolutely mortified at her dad having an FWB while Rinku is just "eh? Why wouldn't they? That's just what Neechan does. /headtilt"
Coming back to this, honestly if they talk again soon there might be some oblivious guilt slinging just because Rinku doesn't know there's a problem on Charlie's end.
"Isn't it great that this place is so accepting? My sister openly sleeping around with every nonhuman in town hasn't hurt her work life or reputation at all!" "That's... nice..."
"That's... nice..."