Oh the taboo, the secrecy. To reveal our deepest, darkest desires to another human being seems so unthinkable. Which is why most of us keep our naughtiest thoughts to ourselves. But surely you've wondered what sexual fantasies get our male counterparts hot and heavy under the collar? Here are eight of the most popular male sexual fantasies, say experts, plus their takes on the male psyche and what to make of these sexy desires.

1. Roleplay

Given that men are highly visual, you probably won't be all that surprised to know that "dressing up" or roleplay is high up there on the list of ultimate male sexual fantasies. Naughty nurses, sexy secretaries and schoolgirls are among the most popular themes for roleplaying. "What we crave gets hard-wired into us between 5 and 8 years of age (based on what was going on at the time) and role plays can either specifically cater to that or simply unleash forbidden ideas," suggests Rebecca Rosenblat, who is a psychotherapist, and a relationship and sexuality expert.

2. Threesomes

Threesomes are another hot male sexual fantasy, but don't fret, it's most likely to remain just that -- a fantasy. Fantasizing a threesome encounter is more about a stamp of approval of his virility, rather than a sign that he lusts after multiple lovers. "Guys like to feel that they can have and pleasure two women at once," says Rosenblat.

Sex coach Dr. Patti Britton suggests that the idea of being unfaithful with other women without actually doing so plays a prominent role in this sexual fantasy. "It allows for 'cheating' without having to breach the relationship," she says. "Perhaps the excitement is escalated by perceiving oneself having the impossible, or even the taboo associated with two women and one man."

3. Paid sex

While they probably wouldn't go down this route in reality, prostitutes can feature in many men's sexual fantasies. "There's a feeling in the male mind that a professional is experienced and ever-willing," suggests Rosenblat. "Plus, he gets to have sex the way he wants it -- and pornographic sex is part of this."

The appeal of fantasizing a prostitute is because it's no-strings-attached sex and there's no performance anxiety on his part because he's not required to please her in bed. "In most 'normal' sexual acts, the man is expected to give or do something to pleasure or please his partner -- but not with a hooker," says Britton.

4. Domination

Having total control during sex is a popular fantasy: He's the master who gets to do what he wants and nothing excites him more than a "sex slave" who enjoys whatever he does. "A powerless male, or one who felt powerless as a little boy can really enjoy taking charge," says Rosenblat.

5. Being submissive

On the flip side, being completely dominated is also a hot fantasy theme for many men and crops up more often than you'd think. "It's quite liberating to have someone take charge of a sexual situation that may otherwise lead to guilt (as in being raised to think of sex as sinful)," says Rosenblat. Imagine just sitting back and letting the horny lady come to you. "The onus is off the guy, because someone else is "making" him do it."

6. Sex in a public place

He might not be bold enough to try this in real life but having sex in a public place where he could potentially be rumbled is another common male sexual fantasy. "Fear of being caught gets the adrenalin going," says Rosenblat. Britton agrees: "For some couples, the top fantasy or 'cure' for lack of libido is often the idea of public sex," she explains. "Fear of getting caught or being seen can be just the right mix to spark a sexual interest."