I think they want to feel the Happiest moment of kissing so that they close their eyes because open eyes never feel like that.
Scientists from Singapore Yau Che Ming, a professor at the National Institute of Education, trying to find the answer. One theory is that, when closing the eyes when kissing is to relieve emotional stress strongly that men and women naturally. The second theory, the couple closed their eyes to escape from reality or the issue at hand. And, to better focus on the perceived feelings of affection for her partner. Another theory reveal a person has a visual perception partner. When the position of the face very close friend and partner, of course my friend could not see him clearly. Well, with eyes closed, picturing the face of your partner can give you the sensation of its own .. funny if when you kiss, you should see her nose hairs are sexy