"Dont expect someone to just know what you want," one post reads. "Tell them." Lehmiller agrees with this advice, and has actually said something similar many times: "Far too many people expect their partners to be mind-readers in bed," he says. "However, this approach usually leads to disappointment. You need to be able to communicate what it is that you want and tell your partner when something feels good and when it doesnt."

Another comment warns of the dangers of using porn as a reference in real life, noting that not everybody has the kind of body that you see in porn, and that certain positions can be awkward or uncomfortable when you attempt them at home. Positions look as awkward as they seem when you're doing it. "Porn can be problematic if you use it as a how-to guide for sex or assume that porn is an accurate reflection of real-life bodies and sex," says Lehmiller.

"However, this isnt to say that porn is inherently bad, because porn can very much be part of a healthy sex life. For example, theres nothing wrong with using porn as a way of vicariously living out a fantasy or seeking a burst of sexual novelty. Just keep in mind that what youre watching isnt a model for sex or the human body."

Another common piece of advice is that orgasms are not required. "Obviously they're great," reads one comment, "but if either you or your partner doesn't finish after you've given it the good old college try, don't get down on yourself about it. Sex should be fun even before the orgasm." People put a lot of pressure on themselves and their partners to orgasm every time they have sex, says Lehmiller: "Sex researchers call this the orgasmic imperative-its basically the belief that sex isnt really sex unless you have an orgasm. And thats a problematic way to approach things. Sex should be fun and enjoyable with or without an orgasm and, ironically, the more pressure you put on yourself to orgasm, the less likely it is to happen. So relax-just have fun, and dont make sex all about 'achieving' some end goal."

A less expected tidbit, aimed specifically at straight men, is: "Do not stay quiet. Moan. We like it." And Lehmiller agrees that being a little noisy during sex can actually be good for everyone. "Research finds that, regardless of gender, people who moan and groan a lot in bed tend to be more sexually satisfied. Why? Because its a form of sexual communication. It conveys to your partner what feels good, which increases the odds of them doing it again. It also shows appreciation for a job well done."