It's no secret that many couples have mixed signals on exactly what their partner wants in the bedroom. To help sort out these "misunderstandings," Ian Kerner, author of several books including "She Comes First," and iVillage sex expert Tracey Cox addressed the most common mistakes both women and men make.

The sex mistakes women most often make:

1. Women don't understand why men don't like to cuddle.

Ian: After sex, men return to the pre-aroused state, women return to a semi-aroused state. For guys it's a total system shutdown. We just want to crash, whereas women want to connect, cuddle, converse, even have more sex. Women shouldn't assume that a guy is insensitive if he's more inclined to snore than snuggle. He's probably just shattered. Think of it as a compliment to the sex you just had.

Tracey: I disagree with this. I think men do like to cuddle! They're just worried their partner might see it as weak and them as vulnerable. I think a lot of the time a man suggests sex, what they're really after is the physical closeness a cuddle would provide

2. Women don't understand the extent to which performance anxieties, self-esteem issues and body-image issues all affect male sex drive.

Ian: Absolutely. Guys have many of the same issues as women when it comes to sex: feeling out of shape, unattractive, not wanting to be seen naked during sex. I worked with one guy who always had to rush to put on his boxers after sex and could never cuddle naked. His wife didn't know what was going on. Turned out he felt very "smallish" after sex.

Also, when guys are stressed out about work/financial issues, it often leads to a shutdown of desire. In both men and women, low self-esteem equals low desire.

Tracey: Men aren't robots. They're humans and worry about the same stuff females do. Also there's pressure on men to provide good sex to women. They expect a lot from men in bed these days, and often expect men to be mind readers, rather than tell them what they want. I'm not surprised men get anxious and their libido dips.

3. Women think that men are always ready and willing to have sex any time, any place.

Ian: No way. As relationships progress over time, women can't assume that guys are Pavlovian dogs that want to have sex every time you ring the bell. The mental turn-on becomes more crucial than the physical turn-on, and sexual desire begins in the brain, not the groin.

Tracey: They do! And they get all upset if he doesn't get an instant erection just by looking at her! It's true that young men probably are ready, willing and able at any point, but once a guy moves into his 20s, the pressure mounts in other areas of his life, like career, and he's as capable of getting distracted by life's problems as she is!

4. Women don't understand how men can differentiate so easily between love and sex.

Ian: One of the reasons is that during sex, women produce lots of oxytocin, a hormone that stimulates a strong emotional connection. As a result, women are more emotionally integrated when it comes to sex. That's why casual sex and hookups often backfire for lots of women. Guys produce little to no oxytocin, and can easily have sex without any sense of emotional connection. It's sex with no emotional strings attached.

Sex Mistakes Men Make

1. Men assume that women have lower desire than men. Men think they have a stronger sex drive than women do, but in most cases they're wrong. The reason why men remain the main sexual instigators isn't just to do with desire. Other factors have a big influence. Women are more likely to do the housework on top of holding down a job, so we're more tired. Hormones also influence our libido, which means our sex drive is less constant. We're likely to feel like lots of sex at a particular time, rather than all of the time. We also tend to attach more emotions to sex, so if our partner's being a right so-and-so out of bed, we aren't going to want to jump in one with him! Finally, there's evidence that while men are aroused by the thought of sex, women are more aroused by sensation. This basically means we might be a bit lackluster at the start, but heat up nicely once things get going. 

Ian: These are the same guys who think foreplay is a peck on the lips and a hand down the pants. If guys actually took the time to understand and nurture female desire, they'd be surprised at the strength of its force.

2. Men assume that all women want romance, not raunch.I always find it quite amusing when I ask men what they think women want in bed because they nearly always put a romantic spin on it. Well, we're not the pure, innocent little creatures you think we are. Women can be just as naughty as men. In fact, a recent study proved that women are more aroused by explicit fantasies than romantic ones. Flick through a Nancy Friday book about female fantasies next time you're browsing the bookstores. She got women worldwide to send her their personal favorites and, believe me, they aren't about men on white horses and romantic walks along the beach! 

Ian: Women have as much of a naughty wild side as men. The cliché is that men are lights-on, women are lights-off in the bedroom, but sex is multidimensional and it's all about having a dimmer switch that goes from romance to raunch. 

3. Men assume that women want guys to look and perform like porn stars.

Tracey: I think men make the mistake thinking porn sex is real sex. It's not! Men in porn are chosen because they aren't the norm. They're larger than life, if you get my drift. Quite frankly, faced with what they have in real life, most women's eyes would water! We don't want that, and we don't want men to behave like they do in porn films. They work their way through the Kama Sutra in about five minutes. In real life, that's just boring. It doesn't impress us if he changes positions all the time. What does impress us is a guy who takes time to work out what we need to get turned on. It's not about the positions "” that's often the least interesting part of sex for women!

Ian: A guy can't get through the day without seeing an ad for an erectile stimulant, getting spam about some sort of penis enlargement pill, or hearing sexual tall tales from the guys in the locker-room. We live in an age where a lot of guys feel like they have to make love like porn stars, and with all the cultural reinforcement, it's hard to believe otherwise.

4. Men assume that if they're ready for sex, she's ready for sex.

Tracey: The male and female sexual systems are different: men get aroused much quicker; women take time. Just because he's ready for sex doesn't mean she is! This is the single, biggest mistake even experienced male lovers make. They underestimate how long women take to orgasm. The statistic most cited for oral sex (which is the fastest, most direct route) is 20 minutes. Most men can climax in about two minutes! And not just that, we need time to get warmed up for sex so we're physically prepared for it. Foreplay isn't a luxury, it's a necessity!

Ian: Guys cycle very quickly through the process of arousal. A guy experiences a sexual moment and presto! He's ready for sex. There's an instant connection between arousal and the desire for sex, and guys assume that women are experiencing the same thing. So to all the guys: Take your assumptions, add 15 minutes of foreplay.