You can switch Pophie to Guardian Mode either in the App or by asking her through voice. In Guardian Mode, Pophie will temporarily stay offline and only keep basic physical reactions, so she won’t disturb you while you’re studying.
As for the frequent giggling, she may have been mistakenly recognizing some of your hand movements as gestures. We’ve improved this in the latest device version, so please check whether your Pophie has been updated to the latest version