You can buy lingerie for the bride as a gift if you are friends. Stick with sweet and pretty. Think about where she shops for clothing and chances are good that she'll like the lingerie from that store. Be sure to include a gift receipt. If you're shopping for someone else, go with a chemise or nightie. You don't have to worry about sizing.
Wear something functional under the dress. It should be great for support. You need a flawless, seamless nude bra that fits really well. You can wear a shapewear bottom that isn't too tight. Since you're going for function, these might not be best for the wedding night. Your seamstress can sew your undergarments into your wedding dress.
For bridal showers, consider contributing to the bride's trousseau. Every bride needs a trousseau. This is lingerie that goes on the honeymoon. Pair it with her honeymoon destination. She needs a few bra and panty sets, some nighties and chemises.
Lingerie expert Jenny Altman shares tips for bridal lingerie.
Here are more recommendations directly from Jenny
Tips for shopping for lingerie (for yourself or as a gift):
Shopping for lingerie should always be fun! Sweet and sexy is always pretty. Lingerie should make you feel confident and beautiful. It should fit well in size and feel like a second skin.
Buy the right size. Chemises and nighties are easier to purchase for others as the sizing is more generic. Bras are harder to purchase for someone else as they are all about fit.
Shop the right style. If you/the bride like Anthropologie or Saks for clothing, buy lingerie there as well.
Wear comfortable, functional pieces under the wedding dress:
Strapless bra: go down a size in the band to ensure a great fit. Pick something seamless that provides maximum comfort and support. (Choose a bra that is silicone free so the bra won’t slip if you are wearing deodorant or lotion. If the bra has silicone, nothing on the skin where the bra sits.)
http://us.chantelle.com/vous-
A high-rise shaper that fits like a panty is a great option. It’s comfortable, leaves no panty lines and can come off/on easily for restroom breaks. Don’t buy shapewear too small, buy your true size so it rests on the skin instead of digging in.
http://us.chantelle.com/shape-
The bridal trousseau:
This is the lingerie package every bride dreams of. Only one time does she get to pack a suitcase full of lingerie for her honeymoon! Choose beautiful pieces that range from chemises and nighties to bralettes and panties. You can include a range of colorful panties, beautiful lacy camisoles, and even soft cotton rompers. This is a lingerie wardrobe, so there should be a few splurges along with a few affordable pieces to round out a beautiful assortment.
Some of my favorite lingerie retailers:
https://www.net-a-porter.com/
http://www.journelle.com
http://shop.nordstrom.com/c/
http://www.kohls.com/search.
https://www.shopbop.com/
http://www.hankypanky.com