Iku continued to stroke Hiro, looking over the interaction between Ume and Hiro like some sort of perverted mermaid.   She wondered, briefly, if Ume was laying some sort of trap acting so...enticing like that.  Part of her wanted to fly out of the water and punish that kitty with pleasure.  Unfortunately, her own modesty and the feline's prohibitions restrained her.  For now, she continued her modest attentions to Hiro's penis...