Blog Posts by Cosmopolitan.com

Women love it when their guy is upset.There are so many factors that go into making a relationship work, but researchers from Harvard Medical School have just tracked down another one-and it's a little random.

Korin Miller

According to their study, men like to know when girlfriend or wife is happy, and women like to know when their boyfriend or husband is upset.

Related: Why Men Fall in Love

For the study, scientists recruited 156 couples and asked them to describe a recent incident with their S.O. that was frustrating or upsetting. Researchers then had each couple discuss the incident for 10 minutes while they videotaped them. They then played the tape back for each person and had them rate how they felt in each moment, as well as how they thought their partner felt.

Related: 13 of The Best Relationship Tips Ever

Researchers discovered that men feel the most satisfied with their relationship when they can correctly guess that their girlfriend or wife is happy. Women, on the other hand, feel the most satisfied with

Can you and your guy bff remain just best friends?It always seems to happen with a guy friend: At some point, one of you wants something more from your relationship. Sometimes, you actually start dating, and sometimes…it just gets awkward.

By Korin Miller

That's why we were psyched to see a new study from Boise State University that pinpointed why some of these friendships keep going, while others totally bomb.

Related: 55 Things You Can Learn From A Guy in 10 Minutes

Researchers interviewed people who had a thing for a friend, as well as that friend, and realized there were some common factors in the friendships that lasted.

Here's the breakdown:

•Both people kept working at it.
Duh, right? But most people shut down when a friend says they're into them, and then…things fall apart. People who said they really valued the friendship and kept working at it stayed buddies.

•They really wanted to be friends.
You've probably been a in a situation where you're tight with a guy, only to have him disappear when you make it clear you

Selena Gomez & BF Justin BieberForget spending the day after a night out untagging unflattering pics of the two of you on Facebook. These tricks will leave you looking your hottest every. single. time.

By Korin Miller

When Selena Gomez tweeted out a photo from boyfriend Justin Bieber's birthday party earlier this week, our first reaction was "Aww." (Seriously, could this couple get any cuter?) And our second was "Wow. Selena looks…amazing."

Taking photos with your guy can be tricky-pose the right way like Selena and you've got a gorgeous new Facebook profile pic. Do it wrong and you're left giving a half-assed story about how you "accidentally" deleted it from his phone.

That's why we consulted award-winning fashion photographer Alexa Miller and celebrity and fashion photographer Eric Ray Davidson for their tips on how to look your hottest in pics with your man. Keep these on the back burner next time you get snap-happy.

Snuggle Up
Pressing your body into your guy (think: tilting your pelvis up against his

Save up for that vacation!Lacking the funds for a much-needed vacay? Try these tricks to beef up your bank account now, so you can be lounging on a tropical island in no time.

By Brittany Talarico

It's that time of year when vacation itch sets in. But it can be a real downer if you don't have the dough to finance a trip. That's why we consulted Jean Chatzky, financial editor for NBC's Today show and author of Money Rules: The Simple Path to Lifelong Security. Follow her cash-saving tips, to shore up money for a beachy vacay...with a little extra for yummy drinks.

Lay Off the Plastic
It's very convenient to just swipe away when it comes to spending, but by only using cards for purchases, you're doing yourself a disservice. "We spend more money with credit than with debit and more with debit than with cash," Chatzy says. "You need to put yourself on a cash diet, so you see where your money is going." Watching hard-earned dollar bills slip away stings more and makes your money harder to part with.

Related:

Now you're married. Should you take his last name?Vanessa Minnillo married Nick Lachey months ago, but she just announced that she's decided to take her hubby's last name.

By Korin Miller

Why did she wait? Vanessa said in an interview that she just didn't have the time before. But ultimately, she said she's just "old fashioned" and wanted to take on Nick's name.

Sure, Vanessa took the traditional route, and research has found that most women do, too, but…there are plenty of women who don't. A recent study published in the journal Social Behavior and Personality found that 18 percent of brides keep their names after they get married. The study also discovered that women with more education or a high-powered job were more likely to stick with their maiden name.

Related: The Best Age to Get Married

Another recent study from Pennsylvania State University found that women who plan to keep their names after they get hitched don't feel any less committed to their marriage than women who take on their husband's name.

Related: 7 Signs

Get busy this leap year!February 29 only happens once every four years-like this one. Take advantage of the extra day to work your man into a sizzling sexual frenzy.

By Carolyn Kylstra

Trying new, naughty things in bed is key to keeping sex with your man hot. Though we know you don't need an excuse to try out different mattress moves, why not dedicate February 29 to it? Since it's a leap year (which only occurs every four years), we have an extra day at the end of this month to play. Go ahead, we dare you to test-drive one of these wild tricks....

Related: The One Trait All Men Love in a Woman

Try 29-ing
Here's a position that feels ahh-mazing for you both: Pull a sturdy chair the wall and kneel on it, so your knees are facing the wall and your toes are pointing backwards off the chair-your lower half looks like the bottom of the 2. Then have your guy (he's the 9) squat behind you, so he's entering you from behind. Your bodies stay super close, creating lots of feel-good friction, says Lou Paget, author of

The best stuff on Earth!Know how sometimes you feel like you're addicted to Ben & Jerry's? Well…you might actually be.

By Korin Miller

According to a new brain scan study from the Oregon Research Institute, your brain pretty much thinks ice cream and drugs are the same thing.

Related: The Diet Kate Middleton Loves

In the study, researchers gave participants milkshakes and scanned their brains. Later, they showed them a photo of a milkshake to measure how much their brain craved it, and then gave them a milkshake.

Over time, those who ate the most ice cream enjoyed it less during the new few weeks, but still wanted more of it. Scientists also found that the area of their brains that is associated with pleasure wasn't activated as much when they had a shake.

Related: How To Lose Weight While Watching TV

That effect is similar to drug addiction-addicts get less and less pleasure from drugs over time, even though they continue to crave it.

Researchers said they decided to use milkshakes in this study

These moves will turn your guy on.Justin Theroux recently confessed that Jennifer Aniston thinks it's hot when he...breakdances. Naturally, that made us wonder about the random things we do that get guys riled up-besides, you know, cleavage and killer stilettos. Real dudes share the moves they find completely irresistible.

By Zoe Ruderman

"During sex, if I'm talking or grunting too much my fiance will clamp her hand over my mouth, and it gets me even more aroused. I like that she knows what she wants-or doesn't want-and has no problem letting me know." -Ty

"I love that my girlfriend hates girly drinks. She usually only sticks to vodka on the rocks, tequila, or beer. There's something really bad-girl hot about it." -Antoine S.

Related: Adorably Weird Things Guys Do That Women Love

"Whenever I'm focused on work or just playing a video game, she just senses when I'm hungry. Suddenly, she'll appear with a snack right as I realized I'm dying for one. It's amazing!" -Ernesto G.

"It's sexy when she gets up for work, but