This may seem like an awkward topic, but really and truly, part of looking good in your costume has to do with your foundation. Just like with makeup, you have to have a solid base before you add anything on top. Fictional characters are often wearing clothing that most of us would never think to wear in public - spandex, boob windows, and other garments are often more fantasy than reality. That necessitates a new strategy when it comes to underthings.
Now, I'm writing from a female perspective; I have no experience with shapewear for male bodies. I'm sure some of these tips will still apply, but others may be totally different. Your mileage may vary!
Also, every product I link to are examples and suggestions. I haven't personally used every product on this list since my costumes haven't necessitated it, but I wanted to provide examples for you so you get an idea of what I'm talking about. Once you know the terminology and what to look for, you can shop wherever you choose.
And don't worry - I'm not including any photos of shapewear/underthings within the post, so feel free to browse away in public!
Modifying your BustFirst and foremost, for any bra, make sure you are wearing the correct size! Even places like Victoria's Secret often measure incorrectly - check out /r/abrathatfits for wonderful instructions and recommendations.
Your needs will depend on your costume and character. There are a few different tools and methods you can use to get the effect you want.
- Strapless or convertible bra. I recommend purchasing this in person unless you are sure of how the brand sizes their bras. A good, comfortable strapless bra can be used for a variety of necklines. It's worth the splurge to get a high quality strapless or convertible bra. A nude-colored bra will be the most useful (a white bra shows under white clothing, while a nude bra doesn't).
- Adhesive bras. These are more like plastic cups that stick directly to your body, and come in a few different styles meant for different types of clothing. You may need something for a backless costume or a low-plunging neckline.
- Minimizing breasts with binding. For a character known for their flat chest or to cosplay a male character, you may need something that binds your chest. For some, a sports bra may be all you need, but for larger-breasted ladies, be sure you are binding safely! I'm not an expert in this myself, but this thread shows how to make sure you are treating your body kindly.
- Creating cleavage. Chances are, your character is drawn with larger-than-life proportions. If you want to create the illusion of cleavage or a bigger bust, this tutorial shows you how with a several bras and some makeup. You can also try one of the super padded push-up bras, like the Victoria's Secret Bombshell Bra, which promises to add two cup sizes. (Remember - this is a totally optional step! You absolutely do not have to mimic the body type of your character.)
The biggest concern with underwear is having lines show through your costume. As with bras, I recommend nude underthings since they won't show up under clothing. There are two types of underoos that I think work best for cosplay.
- Seamless. As the name implies, this type of underwear shouldn't show through your clothing. If you like a more full-coverage undie, this is your best bet.
- Thong. They actually have seamless thongs, but your standard lacy thing should do the trick. This works well for costumes that show a little more booty.
Shapewear makes a huge difference in my comfort level in a costume. I am comfortable with my body and encourage everyone to fall in love with themselves, but I typically don't dress like the characters I cosplay. For me, shapewear bridges the gap between what I typically wear and my costume. It's totally acceptable to cosplay without shapewear of any kind - it's certainly not a requirement - but I think a lot of beginning cosplayers don't realize that many people use shapewear to make everything a little smoother (and I know, at least for me, everything photographs better and I'm much more satisfied with the outcome). It's one of the tricks of the trade, really.
There are two main types of shapewear that I think work for the majority of costumes. They are a little pricey, but you can wear them with many costumes and even for special occasions, so that makes the cost per wear a little more reasonable.
- Full-body. I think this type of shapewear was invented for superhero spandex! This is essentially a leotard with an open bust to fit any neckline.
- High-waisted briefs/shorts. I definitely wear this type of shapewear more often. It's less expensive and usually covers everything for my costumes, but may cause weird lines underneath a superhero-style leotard. I prefer the briefs over shorts since I've never been able to get the shorts to stop rolling up.
My last cosplay trick is one I wish I'd known about before I started. Traditional pantyhose have never worked for me - my legs are much paler than the palest shade - so I assumed I'd always have to go bare-legged. It turns out that's not the case!
Dance tights are different from your old-school pantyhose. They don't have a control top, which may show depending on your costume's bottom half, and they make them in shades that are nearly transparent. It's how you get that "I have perfect legs" look without it looking like you're wearing anything. Plus, I always feel more comfortable in them because it feels like I'm wearing pants, even if I'm in booty shorts.
The one tip I have is to be extremely careful - dance tights are delicate and prone to ripping. I always pack an extra pair to the convention, just in case.
Confidence is Key!
I think the biggest tip for looking good in your costume is to feel good about yourself, and for some, that means investing in shapewear or making sure you have underthings that fit well. I hope this overview proved helpful and answered all your burning underthings-related questions!