The answer refers specifically to American Sign Language, and should not be misconstrued to refer to any other sign language.
Since I know this answer I will let you know. It is not a secret. You either finger-spell it, or you point to the side of your buttocks with the index finger of your dominant hand (modified X hand-shape). You will use either of those two formats depending on the setting and context of your sentence. For example, it would be better to finger-spell this word if you are in the Sanctuary of your church... as the second example might appear obscene to onlookers. You do not have to touch it or pat it... many novice signers make those adaptations out of uncertainty. The pointing example is made with a quick repeated movement. You may also mouth or say the word if you are talking to a lipreader or person who is hard of hearing.
In American Sign Language, the sign for "anus" is made by forming the letter "A" with one hand and twisting it near the side of the body. It is important to use respectful and appropriate language when discussing body parts in sign language.
You can't speak sign language but you can "sign".
In American Sign Language, you can sign "WHEN YOU BORN?" to ask someone when they were born.
To sign "Are you happy?" in American Sign Language, you would sign: YOU HAPPY? with raised eyebrows.
You sign it.
You make an I in sign language and then point to your head and then nod.
In American Sign Language (ASL), you can sign "I know" by pointing to your head with your index finger.
You can't really say it, can you?
A sign language teacher. That's what my students call me.
To sign "Are you mad at me?" in American Sign Language, you would sign: "YOU MAD ME?" while raising your eyebrows and looking concerned.
The local girls use the sign for 3 then the sign for light.
In American Sign Language (ASL), you can sign "emo" by fingerspelling the letters E-M-O.