An unexpected flash of skin under a sheer fabric can be sexy and sophisticated on a date, at a party, even in the office.

But with anything much more than a sliver, it’s easy to cross the too-much-of-a-good-thing line. And there’s no taking it back.

Just ask Tom Mora, women’s design director at J. Crew, who’s created sheer beach cover-ups stylish and elegant enough to be worn as tops and dresses. But, he says, wearer beware: “You should wear a slip, or a cami and brief. They are great pieces but their real intent is for a swimsuit to be underneath.”

He adds, “I don’t want to go into a restaurant and see someone in a completely sheer top.”

At least there, you can look down at your plate. What about the office when sheer fabrics do what they are supposed to do and draw the eye to a particular place?

Remember what your mom said: “Eye contact,” advises Audrey Slater, fashion director at Redbook magazine.

“This trend is definitely peaking this year, she says, “but it’s not a trend for everyone, anytime and everywhere.”

Slater says she’d much rather see a sheer panel or inset than a whole sheer garment. She definitely doesn’t want to see the bra of any of her peers and colleagues across a desk, but a sheer panel at the yoke from the bustline to neckline that shows bra straps “is an acceptable strategy.”

Lisa Axelson, creative director at Ann Taylor, says she loves the look of a gown with a fully sheer or lace back, but it’s a special occasion look, a really special occasion. For daily life, she’d recommend an elongated pencil skirt that hits below the knee with a sheer blouse that has a matching camisole. Navy would be a lovely color.

For an evening work-related event, she likes a black lace blouse with a full-coverage black bra under it and black trousers.

There always has to be balance to the outfit, and that’s never more clear than with something sheer, Axelson says. If there’s sheerness to the top, the bottom should be modest, while a sheer hemline is best complemented by a demure top.

Choice of undergarments is, of course, important when everyone else can see them. There is the subtle, almost shadowy look of wearing the same color slip or tank to match the sheer garment, or you go bold with a contrast color. Perhaps the most interesting illusion is created with an undergarment that matches your skin tone, she says. (It’s a trick done on the red carpet all the time.)

Either way, make sure the underpinnings are pretty, says Norah Alberto, fashion director at Maidenform. “Take an extra step in the morning and take a long look in the mirror — a 360-degree look, please — because when you are walking down the street we are seeing all of you if you’re in something sheer,” she says.