There's a feeling people get from a good kiss that's just hard and just hard to explain. Women compare it to "melting butter" and being "hit by a wave," according to a recently conducted online survey. Men describe it as similar to "vibrations at a concert" or a "three pointer at the buzzer to win the NCAA basketball tournament," according to the same survey, sponsored by SMINT Powermints in conjunction with the release of the Drew Barrymore movie Never Been Kissed.

On the surface, the SMINT sponsored survey appears to be more of a cheesy product promotion than a strict scientific survey. Let's face it, how can anyone compare a good kiss to a buzzer beater to win the NCAA championship when there is probably nothing that compares to hitting the game-winning shot? And for the guy that does that, there would probably be a lot more than just kissing going on after the game.

That's where the science of kissing comes in.

Experts believe there is a whole lot of physiology behind the warm and fuzzy feelings that accompany a good kiss. It's all about dopamine, neurotransmitters, pleasure receptors and the like.

Feelings of passionate love, often but not always a contributing factor to a really good kiss, are believed to stimulate the same type of brain activity as parachuting, bungee jumping, distance running or other sports activities, says Marta Miana, a UNLV psychology professor specializing in sexuality and health psychology.

In a nutshell, these types of activities cause the brain to experience a surge in norepinephrine, dopamine and phenylethylamine (or just PEA to some), Dr. Miana explains. These neurotransmitters attach to the so-called pleasure receptors in the brain to create feelings of euphoria, giddiness, elation and the like. Components in amphetamine drugs are similar to these same neurotransmitters, which is why these drugs create similar feelings, according to modern science.

Any of these activities can be addictive, because the pleasure receptors crave a certain level of the different neurotransmitters. For a variety of reasons believed both genetic and environmental, some people are more susceptible than others to certain types of addictions--drugs, alcohol, skiing, shopping and maybe even sex--based on the type of neurotransmitters the activities produce and the brain craves.

So you're a guy. You feel the firm touch of your girlfriend's full, soft lips pressed tightly upon your own. Maybe there's even a little tongue involved. You're feeling pretty good. And you want more.

Does that make you a sex addict?

Not necessarily.

Is sexual addiction a bona fide disease or just a scam that psychologists created to justify research and book sales?

There apparently is no clear answer.

The National Council on Sexual Addiction and Compulsivity contends that addiction to sexual activity can be just as destructive to an individual as chemical dependency.

"For most people, sex enhances the quality of life," according to a 1991 NCSAC report posted on this agency's well-designed and seemingly credible Internet website. "However, about 3 percent to 6 percent of Americans have sexual addiction. Through their addiction, they may injure themselves physically, experience psychological distress, lose their livelihood and ruin meaningful relationships.

"Sexual addiction often coexists with chemical dependency, and untreated sexual addiction contributes to relapse to chemical use. These patients not only endanger themselves but also put their loved ones at risk for AIDS and other sexually transmitted diseases."

Dr. Miana is like many psychologists with reservations about characterizing sexual addiction as a bona fide disease. For someone involved in a monogamous, loving relationship with his or her spouse, there may be no such thing as too much sex. However, compulsive sex often leads to conduct that is immoral, like extramarital affairs, or even illegal, like solicitation of prostitution, pedophilia or worse. And engaging in compulsive behavior often leaves a person with feelings of remorse or guilt.

Dr. Miana declines to pass moral judgment on others, but she believes a person should seek help for compulsive sex if they start to feel bad about their conduct and/or engage in activity that harms others.

"If a person is feeling badly about it, then they have a problem," she says. "If they don't feel bad, and they aren't doing anything injurious to themselves or others, then that is not a problem that needs psychological attention."