Do you know why you get so turned on from a kiss? Read on to find the answers then check out our expert tips on how to kiss!1. There are tons of nerve endings... ...in your lips (100 times more than in your fingertips!) that stimulate desire. That's why smooching before, during, and after sex can be extremely arousing and satisfying. Source: Krista Bloom, PhD, author of The Ultimate Compatibility Quiz2. Forty percent of men say that... ...a really long, steamy kiss will get them immediately ready for sex. (Thirty percent said that grabbing their crotch will do it. Duh.) Source: Cosmo Poll, April 20093. Pay attention to those "See ya later" pecks. If your guy... ...routinely only gives you a quick kiss on the cheek when saying good-bye, it could be that he's guarded and doesn't emote easily. If this is a more recent development, it's a warning sign; he may be feeling ambivalent about the relationship. Source: Body language expert Tony Reiman4. Instantly turn up the kissing intimacy by... ...closing the "A-frame": a smooching stance in which you and your guy are in the middle of a smooch but your hips are a mile apart. By pressing your hips together, the degree of desire quickly rises. Source: William Cane, kissing coach and author of The Art of Kissing5. The best way to kiss a guy's ear? Kiss and... ...suck on his earlobe for a moment and then trace the outline of his ear with the tip of your tongue. (Bonus points if you whisper something naughty to him.) Source: Ava Cadell, PhD7. Men are more than twice as likely... ...to have sex with a bad kisser than are women. Source: eHarmony.com, "What Men and Women Want in a Kiss8. When coy kisses aren't going to cut it... ...here's why you should let loose: Passionate kisses elevate your blood pressure and cause your heart to beat faster, getting you more excited, and making it easier for you to reach orgasm. Source: Ava Cadell, PhD9. Fifty-four percent of women... ...between the ages of 18 and 24 say they've kissed another girl. That number drops to 43 percent for those between 25 and 34. Source: Cosmo Poll, December 200810. During the Middle Ages, people signed legal contracts... ...by making an "X" on the document and then kissing it to pledge their honor. That's how XX became shorthand for a smooch. Source: Kissing: The Complete Guide by Tamar Schreibman