Anal sex means penis-in-anus (butt) intercourse. Some people enjoy anal sex, and some people don’t like it at all. Either way is perfectly fine. If you don’t like it or don’t want to try it, it’s not ok for someone to pressure you into it. Sex should feel good and be comfortable for both of you.
Anal sex can hurt if you’re not relaxed and don’t use lubricant. The anus doesn’t make it’s own lubrication like the vagina does, so using lube helps the penis (or a sex toy) go in the anus easier and keeps the condom from breaking.
Don’t use anything with oil in it, like Vaseline, lotion, or baby oil. Oil-based lubes can weaken a condom and make it more likely to break. You can get safe lubricants (water or silicone based) in the condom aisle at drug and grocery stores.
Listen to your body. If anal sex (or any sex) hurts, stop doing it. Sex that’s painful or uncomfortable shouldn’t continue and your partner should respect that.