adding 'recommend to a friend' button to menu

I have a client who made a weird request. he wants me to add a ‘recommend to a friend’ button between two menu items and when you click on it will take you to a page or a popup that will allow you to enter up to 3 email addresses. I told him that I never saw anything like it and if it were possible, it would be extremely difficult. any feedback? thank you in advance. souleye