Sex education in the US is somewhat lacking. Since the mid-1990s, over $2 billion has been spent on abstinence-only sex education programs in the US. Trump has indicated that he would like to increase spending in this area, at the expense of sex education that informs teens about contraception and protective sex.

Safe sex isn't the only thing you're not being taught in school, it appears, as a mega-viral thread has shown. In a thread that's been shared well over 100,000 times, sexual health advisor Kelly Grove explains a few things about sex people don't appear to know yet, using some interesting props you'd probably never see in school.

"I went to a private school and all they taught [was] abstinence," one user wrote on Twitter, in praise of the videos. "I never even learned parts of the body like this I had to teach myself. We weren't allowed to talk about sex and I feel like that’s dangerous because it opens people up to STDs and teen pregnancy because they're not educated."

Kelly started by explaining some basic anatomy that a lot of men might have missed out on if they didn't even learn about condoms at school.

She moved on to explaining how orgasms work. 

And the importance of foreplay.

Some of it is stuff that we feel people should definitely know, and yet, judging by the replies and amount of retweets it's getting, they just... don't.

She then went into some myths about penis size and virility, and racist marketing of larger condoms.

The thread has a ridiculous number of shares, with men saying they've never been taught this stuff and women saying they wish they had been.

Many people expressed annoyance that they hadn't been taught any of this in school already, but were thankful to Kelly for sharing the sex education they felt they shouldn't be finding out this late.

Grove works as a Sexual Health Coordinator in the Center for Health Advocacy and Wellness at Florida State University, working to improve education and health at the university.

"Sexual education in the United States is severely lacking and the vast majority of our students have not had comprehensive sex education," she said in an interview with Her Campus at Florida State, explaining why she does what she does.

"Not educating individuals about sexuality leads to grave results... 1 out of 5 college women will be sexually assaulted by the time they graduate. 90 percent of people with disabilities will be raped in their lifetime. And suicide rates among LGBTQIA+ youth are higher than any other demographic. We can bring these statistics down by teaching students about safer sex, consent and sexual diversity.  Education is the key to healthier and safer sexual lives."