How close is too close?

Someone asked us:
Q. Hi, I was wondering what are my chances of getting pregnant if my boyfriend ejaculates close to, but not inside, my vagina? Thanks!
Hi! The best way to avoid getting pregnant is to steer clear of your boyfriend’s ejaculate, because pregnancy can happen when sperm gets in the vagina or on the vulva.
That being said, the most likely way to become pregnant is through unprotected vaginal intercourse. But if you and your boyfriend are rubbing up against each other with your clothes off, there’s a small chance that his sperm may come into contact with your vulva or vagina — which can cause pregnancy, even if you don’t technically have vaginal intercourse.
If you want your boyfriend to keep from ejaculating in the neighborhood of your vagina, you may want to consider using condoms. Condoms will also reduce your risk of getting an STD. And it’s always a good idea to talk with your boyfriend about what kind of birth control you want to use before you hit the sack.
-Amy at PPFA