In addition to consent, it’s also important to talk about using barrier methods to prevent sexually transmitted infections and birth control to prevent pregnancy (if applicable).

Protection from STIs: Barrier methods

Barrier methods such as external (“male”) condoms, internal (“female”) condoms, and dental/oral dams prevent STI transmission by providing a thin physical barrier between sexual partners. When used properly, these barriers prevent direct exposure of skin and fluids that could transmit STIs. External and internal condoms can also prevent pregnancy.

A few key things to keep in mind when using barrier methods:

  • Make sure you have consent from your partner(s) before sexual activity. Learn more about asking for consent.
  • Always check the expiration date of the barrier methods (condoms and oral dams), which will be printed on the exterior of the barrier’s packaging. Do not use the barrier if it has expired, as it is more likely to tear and break.
  • Put on or place barriers before any sexual contact for greatest protection against STIs (and pregnancy, if applicable).
  • Avoid cross-contamination by disposing of each barrier after one use and changing barriers if you change sex acts. For example, use a new condom if you switch between vaginal and anal sex.
  • Do not use oil-based lubricant such as baby oil and Vaseline with latex barriers because oil-based lube will increase the chance a barrier will tear. Always use water- or silicone-based lubricant with latex barriers.

Plan ahead: If you might have sex, purchase or acquire barrier methods in advance so it’s easy to find and use a condom and/or dam in the moment. If you currently live on-campus, you order free safer sex supplies from the Frisky Husky Program.

Check out this video that covers the major barrier methods.

Frisky Husky Flowchart (*Frisky Husky ordering is now open for the Fall 2021 semester. Click here)

Flowchart on what kinds of protection is needed for different sexual encounters.

Sexual health supplies: Types of barrier methods

External condoms (“male” condoms)

An external condom is a barrier for use during oral sex with a penis and when inserting body parts or sex toys vaginally or anally. External condoms protect against many STIs and pregnancy (for vaginal intercourse with a penis). Most external condoms are made of latex, so if you or your partner(s) has a latex allergy, use latex-free external condoms or internal condoms instead. Northeastern students can order supplies through our Frisky Husky Program.

Instructions for using external condoms:

Internal condoms (“female” or FC2 condoms)

Internal condoms, sometimes called “female” or FC2 condoms, consist of a nitrile sheath and outer ring and a polyurethane inner ring. They protect against STIs when inserting body parts or sex toys vaginally or anally and are latex-free. The end of the internal condom with an inner ring goes into the vagina/anus to keep it in place and the outer ring remains outside the vagina/anus. Some people may opt to remove the inner ring if inserting the condom anally. It is important not to remove the inner ring if inserting the condom vaginally.

Internal condoms work the same way external condoms do. Internal condoms can actually provide more protection against STIs by covering a greater surface area of skin outside the vagina or anus than external condoms do. You can insert an internal condom up to 8 hours prior to sex. Some people find internal condoms are less restrictive on a penis than external condoms.

Written instructions for using an internal condom vaginally.
What is a female (internal) condom?
Female condom overview
Female condom information from Planned Parenthood

Oral/dental dams

Oral (dental) dams provide a thin barrier during oral-vaginal and oral-anal contact. They are similar to the dental dams that dentists use, except they are larger and thinner for better protection and increased sensation. When used properly, they protect against STIs and other infections transmitted during oral sex.

To use an oral dam, check the expiration date on the package. If it hasn’t expired, carefully remove it from its packaging, unfold it, and hold it flat over the vaginal opening or anus during oral sex. You can add lubricant to the side touching the person’s vaginal opening/anus for increased pleasure. You do not need to stretch or pull the dam to use it.

Be careful not to flip over the oral dam once you start using it. Consider marking one side of the dam with a non-reversible symbol or letter in permanent marker. That way, you will know which side touched one person’s genitals/anus and which side touched the other person’s mouth. Dispose of each dam after one sex act: do not reuse or flip over dams.

If you don’t have an oral dam available, you can convert an external condom into a dam by carefully cutting off the tip of the condom and along the length of the condom. See instructions and videos below for more guidance.

Personal lubricant

Water-based personal lubricant (“lube”) can increase sensation, reduce friction, and lower the risk of a barrier method ripping or tearing during sex. Water-based lubricant is safe for use with any barrier method and all sex toys and won’t stain sheets or clothing.

Silicone-based lubricant is safe for use with barriers but it may change or destroy the surface of silicone-based sex toys. If you choose to use oil- or silicone-based lube instead:

  • Do not use oil-based lubricants (Vaseline, lotion, mineral oil, coconut oil, etc.) with latex barriers as they can greatly increase the chance the barrier will rip or break.
  • Do not use silicone-based lubricants with silicone sex toys, as it can deteriorate the surface of these toys.

Trusted information about lube:

Go Ask Alice! What is Lube?
ONE: Lube Love: Why Lube Is Your Friend

Talking to your partner(s) about barrier methods

Using barrier methods such as condoms and oral dams during every sex act will reduce the risk that you may contract or transmit an STI. There are a few things to keep in mind in talking with your partner(s) about barrier methods:

  • Again, find a good place and time to bring up barrier methods. Ideally, you should try to have the conversation before the “heat of the moment” when you are in intimate. It can be a harder conversation to discuss barrier methods in the middle of sex.
  • State that you want to use barriers or ask your partner(s) about them:
    • “Do you have a condom? I want to make sure we’re both protected from STIs.”
    • “Just so you know, I always use condoms.”
    • “Have you ever used a dam? I have a spare one in my bag…”
    • “I have a better time when I use condoms/dams because I’m relaxed and not as worried.”
  • In a healthy relationship or sexual encounter, your partner(s) should be concerned about your comfort and safety and be willing to use a barrier method when you ask to use one. If they are reluctant or unwilling to use a condom or dam, you may choose to stop sexual activity altogether.

Remember, your health, safety, and comfort are important and you should not feel pressured to have sex without a condom or dam if you want to use one. Wanting to protect your health by using a condom or dam is NOT a sign that you don’t trust, care for, or love your partner. If you express a desire to use condoms or dams, your partner should not pressure you to go ahead with sex without them. You have a right to say “no” or “stop” to any sexual activity at any point, including sex without condoms or dams.

You can also plan in advance what you might say if your partner(s) is reluctant to use a barrier method. Mount Sinai’s Adolescent Health Center has suggestions of how to respond if someone says they do not want to use a condom. Planned Parenthood also has suggestions of ways to talk about barrier method use with partners.

UHCS and the LGBTQA Resource Center provide condoms for free.


If you are having vaginal sex and wish to prevent pregnancy, talk to your partner(s) about methods of contraception. It’s important to speak with your partner(s) about both preventing both pregnancy and STIs if you have vaginal sex, since some forms of contraception might not protect you against STI exposure. Barrier methods such as internal and external condoms can prevent both STI transmission and pregnancy, while other forms of contraception, such as hormonal birth control pills, only prevent pregnancy—not STI transmission.

Overall, 28.1% of Northeastern students reported using withdrawal or “pulling out” prior to ejaculation as a pregnancy prevention method.* This method requires accurate timing, self-control, and trust to ensure that no semen comes into contact with the vagina or vulva (outer genitals around the vagina). In a “typical use” scenario, it is only 78% effective—meaning that 22 of 100 people who only use the withdrawal method to prevent pregnancy will become pregnant within a year.

In addition, the withdrawal method provides no protection from STIs. The only way to reduce STI transmission is to use barrier methods to reduce direct exposure to STIs via skin and fluid contact or to avoid sexual activity altogether.

What if my partner doesn’t want to talk about STIs or pregnancy prevention? What if they refuse to use a condom even though I want them to use it?

If your partner is unwilling to discuss STIs or pregnancy prevention, or they do not want to use barrier methods/contraception and pressure you to move forward without it, this is a red flag. Remember, your health and comfort are important and you can turn down any sexual activity that makes you uncomfortable or puts your health at risk in a way you want to avoid.

*This data was collected in a Northeastern University 2018 National College Health Assessment.