There are hundreds of millions of nerve endings all over the human body, transmitting information to the brain at a speed of 225 mph. In Planet Love Match's recurring feature "E" is for Erogenous Zone, we explore the world of pleasure that's available when you expand your focus to include every part of your lover's body.

This week: a sex study about kissing provides tips for lavishing attention on the lips.

1. A lot of people say that lips are the first thing they notice on a person, and researchers agree that lip shape is a key factor in sexual attraction. Men tend to notice lush, full lips on women, which could make some biological sense. In women, fuller lips are a sign of higher levels of estrogen, which is linked to higher fertility.  When looking at men, women tend to prefer lips that are neither to full nor too thin, and to like lip shapes that do not have curves that can be interpreted as feminine.
2. Lips are one of the most obvious erogenous zones because of their role in kissing, but one of the first to be neglected with a relationship gets too comfortable. Couples who have been together for a long span of time tend to kiss less than those who have just started dating. Adding long, passionate kisses back to your routine is a great way to reconnect with your partner and bring back the heat.
3. There are 100 times as many nerve endings in your lips as there are in your fingertips. This makes them an important center for sexual arousal. During passionate kissing, try sucking on the upper or lower lip, or gently nibbling.
4. It's worth it to work on your kissing skill! According to a study performed at Albright College in Pennsylvania, when rating the odds that they would want to have sex with someone they considered a bad kisser on a scale of zero to four with four being the most likely, the male response averaged 2.2 while females responses were a dismal average of 1.24.
5. Want to get your lover going? Study respondents said that open-mouth deep kissing is likely to get them hot and bothered.

Photo: liveandrock