We learned just last month that 65 percent of Americans report having unprotected sex—and nearly half of them are never using a condom during sex.

Now, a new study published in the Columbia Journal of Gender and Law reveals that some guys are slipping off the glove during sex without their partner’s consent, a phenomenon coined as “stealthing.”

That’s right, some guys actually think this type of behavior in bed is okay. But as Sinead Ring, Ph.D., of Kent Law School points out in an article published by Broadly, consenting to sex with a condom does not necessarily mean that consent still stands if you decide to slip it off mid-act without letting your partner know. A Swiss man was convicted of rape for this very reason.

Study author Alexandra Brodsky, J.D., told the Huffington Post that she decided to study “stealthing” when she started Yale Law School in 2013. Many of her female friends were experiencing disrespect and even violence from their sexual partners at the time.

You already know that having sex without a condom puts both parties at risk for STDs and unwanted pregnancy, but women in the study revealed that “stealthing” can leave lasting emotional damage, too. Many women noted the fear they felt after they discovered what had happened, the emergency contraceptives they had to pay for, and the trust issues they experienced because of the situation.

To make matters even worse, there are guys out there that actually encourage this type of behavior and even offer each other tips on how to pull it off successfully, Brodsky found. She hopes that highlighting this practice will change the way we all talk about sex—and redefine the laws of consent.

“One of my goals with the article, and in proposing a new statute, is to provide a vocabulary and create ways for people to talk about what is a really common experience that just is too often dismissed as just ‘bad sex’ instead of ‘violence,’” she explains.