Anal sex is sex in which you stimulate the anus.
This can be done in various ways. You can lick around the opening, insert a finger or dildo or have anal intercourse.
Before you have anal sex with someone else it’s a good idea to explore your anus when you are alone. Get acquainted with the muscles around your anus and the shape of your rectum.
When you feel at ease with your own anus, it’s easier to enjoy anal sex with a partner.

More about this sensitive spot
The anatomy of the anal muscles
Be aware of the shape of the rectum
Is anal sex safe?
I think I am hetero, but I often fantasize about anal sex . Does that mean I am gay?
Will it hurt when my boyfriend puts his penis in my anus?

See also: anal beads and butt plug