If he’s currently sleeping with someone else
He should tell you this fact out of respect. However, if he fails to mention anything, just ask him if he’s currently single. You should always know someone’s relationship status before jumping into bed with them. You don’t want to accidentally end up being the other woman.
His sexual history
You don’t have to know exactly how many girlfriends he’s had but you should know a brief history. This means you should have an idea if he’s been in some serious relationships or if he’s someone that just sleeps around. This is important because if he’s had serious relationships, he’s more likely to be respectful and have probably been with less people, which mean less of a chance for STDs.
If sex is a big deal to him or not
This really depends on how far along you are in your relationship because if you’re about to have sex with a guy you’ve just met, he probably won’t make a huge deal out of sex. But, you should be aware of what sex would mean to the relationship you currently have before sleeping with him.
His last name
First of all, why would you want to have sex with someone you know so little about? Knowing his last name should honestly be within the first few minutes of your conversation. This should definitely be covered before you get under the sheets with him.
If you feel safe around him
The most important thing for you during sex is that you feel safe. You should always know how you feel before allowing yourself to be completely vulnerable around someone. If you have sex with someone who you don’t feel safe with, you could end up not enjoying the whole thing and even regretting it later.