Remember when Valentine’s Day used to be simple? When all you had to do to impress your crush was to make a heart out of paper doilies or tape a cheap cherry sucker to the side of a cardboard valentine? Well, those days may be long gone, but luckily they’ve been replaced with something just as simple: the gift of sex.

Just as a bouquet of roses and a box of chocolates has become the requisite Valentine’s gift, so too has the promise of Valentine’s sex. The gift of sex comes in all shapes and sizes, but one of the easiest to pull off is lingerie. Whether you’re a man or a woman, lingerie is the perfect present to both give and receive on Valentine’s Day. Just follow these easy gift-giving tips.

For Men

There are two directions you can go with when shopping for lingerie. There’s the romantic, lacy bra-and-panty set that says, "I love you and think you’re beautiful," and there’s the sexy, see-though number that says, "I love you and think you should be naked."

When shopping for cute, romantic lingerie, the most important thing is to take a peek in your lady’s top drawer. What type of stuff does she already own? This will give you an idea of what she’ll feel the most comfortable in and enjoy wearing. Does she prefer cotton or satin? Lace or padding? Pastels or black?

While you’re at it, jot down her sizes. If you arrive at the lingerie store without a clue to her size, feel free to point out similarly sized women in the store to help your salesgirl determine the right size. And don’t forget the most important rule of lingerie shopping: if you have to guess, GUESS SMALL. Think she might be a medium? Get her a small. Think she might be a large? Get her a medium, because God help you if your size 7 wife sees an "L" on the inside of her g-string. If it’s the bra size you’re unsure of, go with a 36-C. This is the most common size and won’t offend her if she’s larger and will make her feel good about herself if she’s smaller. She can return anything that doesn’t fit on her own.

If you decide to go the naughty route, just make sure she’s game. Most women will love a sheer slip or will be happy to wear a garter belt and thigh-highs for you. There are some women, though, who will find a fishnet cat suit or crotchless panties stupid, if not insulting. Just ask Brett*, 23, who learned this the hard way.

"Victoria’s Secret is so G-rated, so I decided to go to a sex shop to find her something. I saw a pair of edible undies and thought, great—this is a gift we both can enjoy! But it didn’t quite turn out that way," says Brett. "They weren’t what I thought they would be—they were more like a paper diaper than a sexy thong. And to make it worse, she wasn’t about it. I thought if she didn’t like them, she’d at least appreciate them for the comedic value, but she didn’t find it funny even as a novelty gift."

Unfortunately for Brett, his visions of a romantic evening together ended with her sitting on the couch fuming and him sitting across the room wondering where it went wrong. "I ended up in a chair by myself, watching TV and eating the thong. To tell you the truth, I didn’t mind too much. They were actually really delicious—like a fruit roll-up."

For Women

Stop bemoaning the fact that "men are impossible to shop for!" You’re thinking too much. Yes, you want to give him a gift that sums up all the love and wonder you have for your man and your beautiful relationship, and one day maybe you’ll find that perfectly romantic gift, but ask any of your guy friends what the one gift your husband really wants for Valentine’s Day is and the first thing he’ll grunt is "sex." And then he’ll scratch his balls.

Lingerie is the perfect gift to give your man. Not only will he have the pleasure of watching it hit the floor as soon as you put it on, but you’ll get to keep it for yourself. It’s the one gift you can buy for yourself and pull off like it’s for someone else.

With this gift, it’s all about the presentation. Tell him to wait in the bedroom while you slip into his "present." Or, if you want to be more creative, leave a trail of tea lights or rose petals leading him from the front door and into the bedroom where you’ll be waiting. He’ll enjoy unwrapping this gift much more than the book of romantic poems you had originally picked out.

*EDITOR's NOTE: Names have been omitted by request of subjects for anonymity.