You can and likely will get STD from doing oral sex on each other if she has it (as well as passing it on if you have something and dont know it). This is part of the reason i honestly rarely use condoms. I've gotten chlamydia from this kind of gross girl from tinder that was a dancer/stripped when i was younger. My gut said "bad idea" do i didn't let her ride my c*ck like she wanted to because i didn't have a condom, thinking i was fine if she just gave me head. Nope.
Oral is something i do and receive basically every time i hook up with a new girl (unless she smells bad down there), and i obviously kiss her before and after oral. Yeah i'm probably stupid, but condoms kill the mood, kill the feeling, amplify LMR, reduce the feeling of intimacy and trust and connection, sometimes they choke my d*ck out and kill my boner, and they don't reduce the STD risk much at all if you're doing oral (unless you use condom and dental dam for oral, which NOBODY does). Plus (IMO) condoms are meant to be used with some type of lubrication on the inside or on my ****. If i put one on dry, it starts to ride up, gain friction and just choke me out entirely after a bit. Not to mention that it's inconvenient when you want to go multiple rounds to have that latex smell/taste going around if you want her to go down on you again after the first round. I actually start out without condoms, and then sometimes i'll put one on after we've been going for a while to A) prevent me from cumming, allow me to go harder and longer if i'm close to it, and any ***/precum that "leaks" out during sex is usually when you're incredibly turned on and close to finishing, for me at least, and B) it allows me to "finish" inside of her, which i like.
I'm not advocating rawdogging it, but this is just what i do. Use your gut when deciding to sleep with a girl, avoid sex workers, strippers or club girls that go out 3 nights a week and **** a ton of guys, and get tested frequently. Life is full of risks, and unfortunately, sleeping with tons of girls is relatively risky behavior.
It's a calculated risk i'm willing to take to live this lifestyle, and it's one of the few risky behaviors that i really do these days. Luckily the most common STDs are quickly fixed with a run of antibiotics or something similar, and generally don't have lasting damage if they are caught reasonably quickly, so i'm willing to accept the risk. Truthfully, the worst part about STDs for most of us would be the embarrassment of having to reach out to partners and tell them they might have it, and having to abstain from sex and alcohol and stuff for a few weeks.