While logged in to your LuvFree account, click "My Profile" located in the navigation menu tabs at the top of the page. Once there, click on "E-mail & Notifications" from the list which will show you several options you have for toggling email notifications. The very top option is for email notifications for new kisses which can be toggled on/off at any time by clicking on the toggle switch. After you have made changes, click the "Save" button at the bottom of the page.
Shy at first