Since I only understand about 90% of it, and I'm feeling to lazy to look up some of the words, I'm just going to translate the gist of it here.
Naoe is going to be Sadako's pet for one day (because it's Sadako's birthday). Sadako is surprised but really happy about it, whereas Naoe is reluctant to let Sadako do what she wants with her. Sadako expresses her eagerness towards the situation and exclaims she won't let go of Naoe.