Couples who share a passionate kiss this Valentine's Day will enjoy sensations of relaxation and excitement because of a complex series of chemical processes, as well as their love for their partners.

The study showed that women need more than just a kiss to experience the same chemical high as men - with additional features such as a romantic atmosphere of dimmed lights and mood music also required.

http://www.telegraph.co.uk/scienceandtechnology/science/4558541/Kissing-feels-so-pleasurable-due-to-hormone-surge-find-scientists.html