Mikuru looked up from her relaxation when Sarah jumped in, confused a bit at first at why she was getting in wearing her normal uniform.  Her confusion only worsened when she yelled at her and grabbed her breasts!  "Eeyah!  What are you doing?  Don't grab my breasts!" she cried out, trying to push Sarah away from her, though she couldn't help but moan at the sudden pleasure from her breasts getting squeezed.  "No... stop, please...." she managed to beg between moans, but it was clear her body was enjoying the attention immensely.