Masturbation, aka the ability to bring yourself pleasure at a moment's notice, is pretty extraordinary. So is the fact that more masturbation aides exist than colors in the rainbow, and then some.

That said, just because you can masturbate with something does not mean you should. This is going in or around your genitals, so you want to make sure it's not going to irritate or infect you in any way. So, for the sake of your sexual health, think twice before using the following the next time you're looking for an orgasm:

1. Your hands are sharp or dirty

But before diving in, make sure your fingernails are not basically under-the-radar threats to your vulva, vagina, and anus.

Sharp or jagged nails can do a number on these sensitive body parts, Jacques Moritz, MD, an ob / gyn at Weill Cornell Medicine in New York, tells SELF. These abrasions-no matter how tiny-can leave your delicate genital tissues feeling inflamed, irritated, and uncomfortable. They can also make you more susceptible to sexually transmitted infections (STIs) by creating openings for infection-causing pathogens to enter, according to Dr. Moritz.

And you should always wash your hands (and under your fingernails) before putting your hands on them ( Natasha Chinn, MD, a New Jersey- based gynecologist tells SELF.

2. Fruits and vegetables

It makes sense that a resourceful person could see a zucchini, cucumber, or banana and get some ideas. But, um, do not.

Whereas sex toys are pretty resilient, food can fall apart, Lauren Streicher, M.D., an associate clinical professor of obstetrics and gynecology at Northwestern University's Feinberg School of Medicine, tells SELF. You should be spending your post-masturbation minutes in a state of bliss, not anxiously trying to fish bits of carrot out of your genitals. They can also have weird, rough angles and edges, which, ouch.

Food and vegetables are not acquainted with, Maureen Whelihan, MD, a Florida-based gynecologist, tells SELF. Though your gastrointestinal (GI) is usually pretty adept at handling this bacteria, your vagina might not be able to, and it could become inflamed or irritated. Chinn says.

And, like many of the objects on this list, you might have a size problem. While it's totally fine to experiment with toys of different shapes, lengths, and widths, you should not force anything into your vagina that hurts. That means the monster eggplant you grabbed at the farmer's market is probably out.

If you're determined to bring (appropriately sized) produce into the bedroom, Dr. Streicher recommends only ever doing it with a condom completely covering the object. Not only will this protect your vagina from some of that rouge of fruit and vegetable bacteria, it will also catch any pieces that break out before they have the chance to float out of reach. That said, a toy designed to go inside you would definitely be a better bet.

3. An electric toothbrush

Given that they are long and can vibrate, electric toothbrushes are practically begging to be used as sex toys. Still, Dr. Streicher advises against it.

While the bristles are great for stimulating your clitoris, they are much more likely to irritate it or even cause microabrasions that make you more susceptible to infection. The same goes for penetrative masturbation; if you put on your electric toothbrush, inside yourself and turn it on, you might scratch, tear, and inflame your tissues. Plus, if it's a used toothbrush, you're discovering yourself up to even more irritation and bacteria.

If you absolutely can’t live another day without knowing how it feels to masturbate with an electric toothbrush, Dr. Streicher recommends wrapping it in a towel or washcloth before putting on your vulva, and just skipping any internal penetration altogether. Even with the barrier, make sure it’s a never-been-used attachment. And, obviously, do not then use the toothbrush on your mouth afterward. Even then, a standard sex toy would probably feel a whole lot better.

4. Candles

Dr. Streicher says some enterprising individuals repurpose candles with masturbation in mind. Though many candles may appear to be great candidates for substitute sex toys, they are usually not.

You’ll want to avoid them for one of the same reasons you’d avoid phallic fruits and vegetables: They can break inside you. The size issue can also be a factor here—candles come in a range of thickness, which is great decor-wise, but maybe not so much for your genitals.

5. A hairbrush

Hairbrushes may seem like great sources of textured stimulation, but these are better kept out of the bedroom. Whelihan says. Their prickly bristles can irritate and cut your vulva, vagina, and anus, which is usually not the goal of a good masturbation session. That said, if you want to use a hairbrush that is not too big for you (rather than the bristled end) and you use a condom, you should be OK, Dr. Chinn says.

6. Anal toys without flared bases

Before you stick anything in your butt, make sure it has a flared base, meaning it widens at the bottom. That will prevent it from slipping past your constricted anal sphincter into your rectum.

For the record, flared-base toys aren’t exclusively reserved for anal play; you can use them for vaginal penetration, too. But it’s much rarer for toys to get “lost” in the vagina than it is for that to happen with the rectum, Dr. Whelihan says.

The vagina is only a few inches long, stopping at the cervix. If a toy slips in, it does not have very far to go. But the rectum is part of the lower GI tract, so a toy can "go up quite a distance," Dr. Whelihan says. And unlike the vagina, which has a pretty uniform diameter throughout, the rectum becomes more of a "puffed out empty chamber" once. Whelihan says. That can make it even harder to retrieve a wayward anal sex toy. So can all the lube you might use during anal play. "That sucker can slip out of your hands in a minute and just go right up in there," Dr. Whelihan says.

If it does happen, try not to panic-there are a few things you can try to help you avoid an emergency room visit. Still, it's best to avoid this altogether by only using sex toys in your butt that is specifically made for your butt.

7. Anything that's just been in or around your anus.

If you've used a toy anally, you need to clean it it to your vagina.

Though your vagina contains a lot of bacteria, your anus is home to different bacteria-specifically, those from your GI tract, like E. coli. It's totally fine for this stuff. But if it travels to your vagina, it can eventually cause problems. Whelihan says.

One potential issue is bacterial vaginosis, which is when "bad" bacteria outnumbers the "good" bacteria in your vagina, leading to symptoms like a "fishy" vaginal odor and urination. If that makes it to your urethra, it could lead to a urinary tract infection, which comes with symptoms like frequent, burning urination and cloudy pee. Not fun. Take a few minutes to make sure that you've been used anally. After that, have at it.