How Should Underwear Fit: The Ultimate Guide

person wearing black underwear

When it comes to underwear, fit can be one of the most important factors. Whether it's briefs, boxers, bikinis, or thongs, it's essential to make sure your underwear fits just right. Not only does the right fit ensure that your underwear is comfortable, but it can also help you feel more confident and prevent any wardrobe malfunctions. 

So, how should underwear fit? We’ll tell you. Read on to discover our ultimate guide to choosing the right underwear for you.

How To Choose the Right Underwear

Is your underwear too tight, causing bulges or digging into your skin? Does your underwear ride up or down? Dealing with wedgies on the reg?

If you answered yes to any of these questions, there’s a pretty good chance that you’re wearing the wrong underwear. Not to worry, though — here’s what to keep in mind when choosing a pair that’s right for you:


First off, you need to choose the right style. Underwear comes in many different shapes and sizes, from thongs and briefs to boxers and trunks, so find the style that works best for your body type and activities.

If you're active, perhaps opt for styles with more coverage. For tighter clothes or everyday wear, briefs are usually a smart choice as they provide maximum support without too much fabric bulk. 


As touched on previously, the waistband should not dig into your skin but instead lie flat against your skin without being too tight or loose. When the waistband is too tight, it can cause discomfort or irritation.

When it's too loose, on the other hand, it can ride up throughout the day and cause bunching, which can be both uncomfortable and annoying, to say the least.

Leg Openings

The leg openings of your underwear should fit snugly yet comfortably around your legs. You don’t want to be bothered by your undergarments riding up or down as you conquer your day. If they ride up during activity or when you sit down/stand up, then they're probably too loose. In contrast, if they feel constricted when standing, they're most likely too tight.

Goldilocks might not have been a polite house guest, but she really did understand the importance of “just right.”


Are you the proud owner of a penis or packer? Try finding a pair of underwear with a comfortable pouch that provides just enough space to keep everything in place while still remaining breathable. It should also allow for easy access!

Many styles often have a slightly contoured pouch so that everything fits well without having to adjust throughout the day due to bunching or shifting around.

Pro Tip: For those who pack, you may want to consider packing underwear. Not sure where to look? Check out our packing underwear here at TomboyX. Combined with our oh-so-soft stretch-blend cotton, signature stay-put waistband, and chafe-free mid-length coverage, these briefs ensure comfort and confidence all day long. 


When choosing underwear fabric, consider what activities you'll be wearing them for. For example, if you're planning on being active, look for moisture-wicking fabrics. Fabrics with a dash of polyester/Spandex will keep sweat away from your body better than traditional cotton fabrics do.

Cotton is generally lightweight and breathable, making it great for everyday wear but not necessarily ideal if sweating a lot (like during exercise). PS: Our TomboyX cotton is OEKO-Tex Certified so that our planet stays as evergreen as our styles.

Love cotton but want something even softer? Get to know our miracle fabric — TENCEL™ Modal. Made from sustainable beechwood — it’s twice as soft as cotton, temperature regulating, and certified biodegradable. Checkmate. 


“Underwear” is a sort of catch-all term, but don’t be fooled by the sleek styles — the differences (and the magic) are in the details.

Here are three types of underwear that go above and beyond:

  • Tucking Underwear: This underwear group offers a comfortable and simple way to tuck. The bikini cut is flattering and durable, made from a double-layered interlock polyester with a one-way stretch that you can rely on.
  • Our tucking underwear is made from a mixture of recycled polyester, nylon, and Spandex mesh for a moisture-wicking, antibacterial, and odor-resistant combination. In fun colors and classic neutrals, this underwear is reliable and gender-affirming. 

  • Packing Underwear: This category of underwear accommodates a FTM packer. Made from silky smooth OEKO-Tex-certified cotton (95%) and a dash of Spandex (5%), these are a comfortable way to affirm your gender.
  • At TomboyX, our packing underwear has a six-inch inseam in classic dark neutrals. In sizes from 3XS to 4X, there’s a fit for everyone. 

  • Period Underwear: This type of underwear is an environmentally-friendly alternative to menstrual products like pads and tampons. These leak-proof bottoms work best for light and medium flow days.
  • Rather than remembering to stuff a handful of pads in your backpack, simply slip on a pair of period underwear and head out the door. They come in styles like hipster, boxer briefs, trunks, and bikinis (and in multi-packs). One pair can hold about eight teaspoons of liquid and are machine washable. 

    Overall Fit

    The overall fit of your underwear should feel comfortable even after extended periods of time—if there is any discomfort after trying on a few pairs, go for another size or style. Check that all of the aforementioned areas (waistband, leg openings, and pouch) fit well and don't cause any discomfort when wearing them.

    What Are the Different Types of Underwear?

    Now that you know what to look for to achieve a comfortable fit, let’s review the different types of underwear. Although there are many, here are some of the most common:


    Boxers are a loose-fitting style of underwear and are usually made of lightweight materials like cotton. This style of underwear offers a more relaxed fit and is often chosen for its comfort. Note that boxers don’t offer much support, so they’re not always the ideal choice for those looking for extra coverage or control.


    Briefs are a famous style of underwear and are usually made from cotton or other stretchy fabrics. They have a classic shape, with an elastic waistband and legs that hit the mid-thigh. Our iconic briefs have reliable support and are awesome if you prioritize a secure fit and extra coverage.

    Boxer Briefs

    Boxer briefs are a popular hybrid of briefs and boxers and offer a flawless balance between support, coverage, and comfort. This form of underwear is often fitted at the waist and has wider legs with a longer inseam, providing more coverage and support.

    They’re ideal for wearing under tighter clothing and are the favorite of people who want the support of briefs with more flexibility and coverage.


    Trunks are a slightly shorter version of boxer briefs, and they provide a snug fit around the legs, making them a welcome selection for those who want a snug fit with more coverage. They’re also often made of a lightweight material, so they’re perfect for those summer days. 


    For those looking to reduce visible panty lines, bikinis, thongs, and G-strings are your answer. Bikinis are an excellent option for those looking for a bit more coverage, with a low-cut waistband and moderate leg coverage.

    Thongs and G-strings are well-suited for those looking to eliminate the appearance of panty lines, as they provide minimal coverage. Our gender-inclusive thongs are crafted from the ultimate duo of TENCEL™ Modal and Spandex for stay-put underwear that’s as soft as a cloud.

    Cheeky Briefs

    Cheeky briefs typically have a low-rise waistband and provide more coverage on the backside, with less coverage on the front. This style of underwear will provide more of a “cheeky” look and are a fan favorite for those who want to show off their curves.

    Boy Shorts

    Boy shorts are a wonderful option for those seeking more coverage. This category of underwear typically has a high waistband and longer legs, providing full coverage and a flattering silhouette. They provide good support through their snug fit and are an ideal option for wearing with tighter clothing. 

    Any Tips?

    As a matter of fact, we have quite a few. Here are some helpful tips to keep in mind when shopping for underwear: 

    Tip #1: Know Your Sizes

    It’s important to know which sizes work best for your body type to ensure your underwear fits properly. Take a few measurements of your waist and hips and compare them to the size chart of the underwear you’re interested in.

    Buying underwear that’s too big or small can make them uncomfortable and cause unnecessary bulk or bunching. If you’re unsure of the optimal size for you, try on a few sizes until you find the one that fits best.

    Check the size chart. Every size chart (like all bodies) is a little different. At TomboyX, we made sure our sizing chart was as inclusive as possible — from 3XS to 6XL — everyone is invited to this party.

    Tip #2: Choose Fabrics Carefully

    Some fabrics can be uncomfortable and cause discomfort, so avoid them if possible. When it comes to softness and the environment, haste makes waste, as the saying goes.

    Seek out fabrics that allow your skin to breathe to avoid itching or irritation. Natural fabrics like cotton, silk, and TENCEL™ Modal are more comfortable and allow your skin to breathe, so they’re typically a better choice if comfort and breathability are important to you.

    Additions from world-famous superstars like Spandex, recycled nylon, and elastane add that “something special” that helps your undergarments move seamlessly with you. 

    Tip #3: Look for Stretchy Waistbands

    Stretchy waistbands provide more support and comfort, so look for them when shopping for underwear. The TomboyX Signature stay-put silky soft waistband is adjustable and will give you a snug fit without being too tight. Such waistbands also offer more flexibility and freedom of movement, making them ideal for anything on your calendar. 

    Tip #4: Replace When Necessary

    It’s important to replace your underwear when it’s worn out or stretched out. Worn-out underwear can be uncomfortable and can cause bunching or pinching, so make sure you replace them with a new comfy pair to ensure optimal comfort and fit. To keep your underwear in good condition, wash them regularly and follow the care instructions.

    The Final Word

    With these tips in mind, you can find the perfect pair of underwear to fit your body and lifestyle needs. Keep in mind that everyone is built differently; there may be some trial and error involved before finding the right fit. 

    Ready to find your next favorite pair of underwear? Check us out here at TomboyX today!


    Packing | Susan's Place Transgender Resources

    TENCEL™ Lyocell & Modal fibers properties: What does TENCEL™ feel like | TENCEL™

    spandex | fibre | Britannica