STEP 1: Figure out her size
Figuring out your girl's size might be the easiest or the hardest part of this process. The best way is to wait until she's at work or away from the house for some reason. Then, you just weed through her underwear drawer to find her size. It may make you feel a little creepy, or maybe you do this kind of thing all the time. Either way, you'll have to dig through her clothing to find her size, because you can't just come out and ask her.
STEP 2: Pick a Style
Oh, you didn't know there was more than one kind of bikini? Sure there is! In fact, there are tons of different styles and a dizzying array of colors and patterns available. But because we're guys, we'll keep things simple here, sticking to the most popular styles. If your girl already has a bikini (or several of them), it might be a good idea to check them out. Then you can decide if you want to get her another one in the same style, or get her something completely different.
To give you a quick idea of a few of the most popular bikini styles, we've provided a handy little interface below with our digital bikini model, Simone. Click the top and bottom styles on the right to see Simone model them for you. Then check out the panel to the left of Simone for a description of each top and bottom. You can even click the tops and bottoms while Simone is wearing them to visit a site where you can buy them.
Triangle Top bikini
The triangle top is a staple in any bikini wardrobe, and it's what most people think of when asked what a "bikini" is. It's called a triangle top because the fabric covering the breasts is (amazingly enough) shaped like triangles.
Bandeau Top bikini
This top offers a little more coverage and is usually just a few pieces of fabric, tied around the back with no shoulder straps.
Butterfly Top bikini
The butterfly top offers about the same amount of coverage as a triangle top, but is cut so that the top of the suit rides lower on the breast for a different look.
Knotted Top bikini
The knotted top bikini is so named because it is tied together in the center with, you guessed it, one or more knots.
Enhanced Top bikini
The enhanced top is cut so that the lines running down the center of the chest have a slight wave to them, which serves to make enhanced breasts look even better.
Sweetheart Top bikini
The sweetheart top is basically identical to a bandeau top, the difference being the sweetheart having shoulder straps which are slightly wider than standard bikini shoulder straps.
String Bikini Bottom
For most guys, this is our favorite type of bikini bottom, because it covers so little. Just keep in mind when picking out a bikini bottom that your woman might not want to feel so exposed.
Whale Tail Bottom
The whale tail is so named because the shape of the bikini (when viewed from the back) resembles a whale's tail.
Pucker Back Bikini Bottom
The pucker back bottom is sewn in such a way that the fabric naturally "wrinkles" in the back, giving an added bit of visual flair.
Shortie Bikini Bottom
It's not quite a pair of shorts, it's not quite a panty, it's somewhere in between.
Shirred Bikini Skirt
Shirred skirts are sewn using a method like the pucker back to give it an all-over wrinkled look. A pair of standard bikini bottoms are often sewn into the skirt part.
Brazilian bikinis are hugely popular right now. The Brazilian offers more coverage than a g-string or thong, and usually rides a little bit lower on the hips.