https://www.bustle.com/articles/64679-does-my-vagina-smell-healthy-5-common-vaginal-odors-explained
Fishy Scent
The idea that vaginas "smell like fish" is used so often to put down women and their bodies that it's almost hard to talk about the times when this pungent scent can signal a real medical problem.
But an intense fishy smell in your deep blue sea can be a sign of two common vaginal infections among young women: bacterial vaginosis and trichomoniasis. Bacterial vaginosis is an infection linked to an imbalance of bacteria in the vagina. It is not an STI, though it can be triggered by sex with a new partner. Trichomoniasis is the most common curable STI in America (though it can occasionally be contracted through nonsexual means). Both infections give off a fishy scent (and often, a white or gray discharge) as a symptom, and both can be cleared up easily with a course of prescription antibiotics.
Metallic Scent
A metallic scent coming off your vag is most common right after you've had your period or had some intimate contact with semen. Both can change the pH of the usually-acidic vagina into something more basic (and thus, differently scented). In both cases, the metallic scent should be temporary.
Yeasty/Bread Scent
Often, yeast infections don't have any scent at all, and so you'll realize that you have them from their other symptoms (thick white discharge and itchiness). But in some cases, your yeastified bits will emit a faint bread-like odor, one that can smell slightly musty.
Musky Scent
A musky scent that smells just like a heavier version of your vagina's usual scent typically means that you've been sweating a lot, or wearing too-tight pants or synthetic fiber underpants (both of which can prevent skin from "breathing," and thus lead to a stronger-than-usual scent). Washing your funky bunch (of vulva) with some mild soap and changing out of your skinny jeans every once in a while should fix things up if you find this scent a little to strong for your tastes.
Rotten Scent
If your vagina suddenly takes on an intense rotten smell, get in touch with your ob/gyn immediately. It's definitely not healthy, and could be a sign of a tampon gone astray in your vagina during your last period, which happens way more often than you'd think. Your ob/gyn has definitely dealt with extracting a long-forgotten tampon before, so don't be shy about setting up an appointment.