Like everything else; no sexual encounter is borne equal. You can have great sex, terrible sex, mind-blowing sex and then boring sex, all with the same person, in the space of a week. Though this seems counter-intuitive, it's really not that surprising once you realise that there are many factors which can influence the quality of your romp.

While we all know that the number of alcoholic beverages you've consumed prior to the fact, as well as something like what you chose to eat for dinner, can affect you and your partner's enjoyment - a recent study has established an altogether more rudimentary factor in the quality of your love-making.

It is reported that one in three American adults do not get enough sleep. Sexual issues are also common, with as many as 45 per cent of women and 31 per cent of men being actively concerned about the state of their sex lives. Now, while these may seem to be distinct concerns - unrelated apart from the fact that they both take place in the bedroom - sex educator and researcher, Laurie Mintz, has claimed to the contrary.

Mintz, who wrote A Tired Woman’s Guide to Passionate Sex did so to help the alleged "countless women" who say that they are too exhausted to be interested in sex. She states that women are disproportionately affected by both sleep problems and by low sexual desire, claiming that the relationship between the two is "indisputable". Certainly, women are not only more likely than men to have sleep problems, but the most common sexual complaint that women bring to sex therapists is, indeed, low desire.

"Strikingly, being too tired for sex is the top reason that women give for their loss of desire," Mintz added.

According to a study referenced by Mintz, getting a good night's sleep can increase desire. The research found that the longer a woman slept, the more interested they were in having sex - just one extra hour of sleep led to a 14 per cent increase in the chances of a sexual encounter the next day. The same study also alleged that sleep was associated with greater genital arousal.

While this particular investigation was conducted with college-aged women, these concerns only become more prevalent in older women, in particular, those going through menopause. A follow-up investigation discovered that among menopausal women, sleep problems were directly linked to a decreased appetite for sexual activity.

And it doesn't just end there. "Interrelated sleep and sexual issues are also prevalent among mothers," Mintz continued. "Mothers of new babies are the least likely to get a good night’s sleep, mostly because they are caring for their baby during the night. However, ongoing sleep and sexual issues for mothers are often caused by having too much to do and the associated stress. Women, who are married with school-age children and working full time, are the most likely to report insomnia. Still, part-time working moms and moms who don’t work outside the home report problems with sleep as well."

Though lack of sleep and insomnia appear to affect women's sexual functioning more than men's, it's apparent that they can still suffer from issues in these areas. Research found that, among young healthy men, a loss of sleep culminated in decreased levels of testosterone - the hormone which is responsible for much of our sex drive. As Mintz corroborates, "Clearly, among men, lack of sleep results in diminished sexual functioning."

So, there you have it - you better rest up folks - lest you want your sex drive to suffer.

So, we've found out what annoys men in bed, and what annoys women in bed, so how about finding out what women actually want? As said in the previous articles, communication is key to all forms of sexual relationships. After all, if you don't know what your partner likes, how are you going to give it to them?

Well luckily for us, women have revealed what they like, and they want more of it. So, listen up readers, if you're looking to give your lucky lady a mind-blowing orgasm, this is what you need to be doing.

There's a wide array of memes about men not being able to figure out the anatomy of the female reproductive organs, with the majority of them focusing on their lack of knowledge surrounding where the clitoris is located. Well, you better whack out the biology book guys, because according to a new study, women want more clitoral stimulation in the sack.

A whopping 73 per cent of the 1,000 women who were surveyed, said that they need more stimulation in order to get them off. 36 per cent of the ladies in question, said that they need direct clitoral stimulation in order to reach the big O, with another 36 per cent saying it made their orgasms feel better.

The survey was conducted by the Indiana School of Public Health and found that just 18 per cent of women said that intercourse alone was enough in order for them to climax; essentially, more work is required. However, even more shockingly, nine per cent of women said they they don't climax at all during a session with their partner, making their sex wholly one-sided and not in their favour.

The survey was conducted on women who were aged 18 - 94 and it turns out that there isn't a right or wrong way to touch your lady when it comes to their downstairs parts.

When participants were asked to rank their favourite ways to be stimulated in the sack, 64 per cent of them said they preferred an up and down motion, 50 per cent liked a circular motion and a some preferred to have several different methods.

As always, it's probably best to ask your partner what she likes, something which study author Brian Dodge reiterates: "The study results challenge the mistaken, but common, notion that there are universal 'sex moves' that work for everyone."

Sexpert Annabelle Knight has revealed that the one position that is most likely to make a women orgasm through just intercourse, is surprisingly, missionary. This is thanks to the fact it was one of the only positions that allows for internal stimulation as well as clitoral stimulation. It seems like the majority of Brits agree with her as well, with the man-on-top being the nation's second favourite sex position with 21 per cent of couples favouring it (woman-on-top is the first).

So there you have it, women want more clitoral stimulation when getting down and dirty. It's not rocket science, is it? Sex is meant to be enjoyed by both partners, so don't be selfish and get on down there!

Everybody wants to have great sex, but sometimes it just doesn't happen, despite your best efforts. Maybe it's because of a failure to communicate, or maybe it's because of a lack of experience, or maybe it's because you both had too many whiskey-cokes. Either way, you assure your partner it was a five star experience, but deep down, you both know it was  a one. (Maybe two stars, tops.)

In her new book, Love Rules, former Cosmopolitan editor-in-chief Joanna Coles explains how to navigate today's tricky new world of dating. Also, she reveals how to experience a satisfying love life, debunking many myths about casual sex: For example, compared to Generation Xers, millennials are more than twice as likely be sexually inactive. People crave intimacy, and many of these hookups go poorly, with only 11% of women reporting having an orgasm. What's more, over 50% of women and men want to stay the night and cuddle after a hookup. That proves guys don't just want flints; they want serious relationships too.

Basically, Coles argues that casual sex isn't casual. If you want to avoid feeling an "emotional hangover," then you should get real with yourself. Here are 21 questions you should ask yourself for a better sex life.

The questions begin by analyzing your sexual history. Let's remember the good times!

1. When was the last time you had good sex?

2. Who was it with?

3. What were the circumstances?

4. Did you have an orgasm?

5. Did you see that person again?

Next, consider your experience with casual sex.

6. Have you ever had casual sex?

7. How often do you have it?

8. Do you have sex to figure out if you like someone?

9. Do you have sex drunk?

10. How often?

11. Do you regularly have orgasms?

Before you commit to having sex with someone, ask these questions:

12. Why are you sleeping with this particular person?

13. Do you just want to have sex?

14. Are you sleeping with him because you want him to like you and you think the act of sex will achieve that goal?

15. Do you think it will be a good experience?

Coles says that it's important to identify your expectations. If you're totally cool with a fling for fun, or you're sure this is beginning of a serious relationship, then that's great. But if you're not sure where this relationship is headed, you might get ghosted by your partner afterward, and feel crushed. Once you're clear about your expectations, ask these questions:

16. What is the potential upside?

17. The downside?

18. Is the equation worth it?

If your partner passes the test, then look for these cues:

19. Does your partner make you feel comfortable and safe?

20. Is your partner sensitive to the boundaries of consent?

21. Can you talk about sexual protection?

Coles says "protected sex is a prerequisite for sexual pleasure," because without protection, people feel anxiety.

Well, hopefully by answering these questions you can experience a better sex life. And if this doesn't work, you can always try ordering those "magic pills" in your email spam folder.

In a related story, these 10 little tips will reinvigorate your love life...