If you and your partner are in a monogamous relationship (not having sex with other people) and you have both been tested (and are STD-free) since your last time having sex with someone else, it is generally considered safe to have unprotected oral sex. If either you or your partner is having sex with other people, or has not gotten tested since the last time you had sex with other people, there is some risk that an STD could be spread through unprotected oral sex. If this is the case, remember that dental dams are your friend. If you don’t have access to one, you can quickly turn a condom into a dental dam. Also, Planned Parenthood endorses the use of plastic wrap when dental dams aren’t available. When in doubt, best practice is always to use protection.
If you don’t know if your partner has been tested recently, ask! There’s no shame in the game. Regardless of gender or sexual identity, it’s a good idea to get tested regularly (and this can even be something you and your partner do together). If you need a place to get tested, Whitman-Walker offers comprehensive testing, counseling, and referral services that are always free of charge. They have a location in Logan Circle, which is easily accessible via the G2 bus. Whitman-Walker specializes in care for LGBTQ+ individuals, but they serve the entire DC community. Georgetown Student Health Services also offers STI-testing and, as long as you have insurance, you should not have to pay for that service.
All of that being said, if you and your partner have both been tested recently and are only having sex with each other, unprotected oral is considered safe (this is true regardless of gender identity). In any other situation, it’s best to use protection.