To give another deviant a direct link to this FAQ answer, use the following code in your comment or forum post:
You prohibit the submission of 'pornographic literature'; what do you consider this to be?
When we mention 'pornographic content' in our policies we are specifically referring to certain subjects which will be clarified below. These restrictions apply to active and stored deviantART submissions, sta.sh submissions, PCP files, etc.
We apologize if the descriptions below are slightly graphic.
Literature which contains the following themes will be considered unacceptable for submission if the reviewing staff determines that the work possesses no redeeming literary qualities. Any work deemed unacceptable will be removed by staff without prior warning.
A literary work may not explicitly detail the act of masturbation.
• Sexual Intercourse
A literary work may not detail graphic or explicit sexual intercourse. This includes descriptions of sexual penetration, oral to genital contact, genital to anal contact, oral to anal contact and may also include certain types of genital to genital contact and oral to breast contact.
This prohibition extends to descriptions of bodily fluids associated with sexual acts such as semen and vaginal lubricants.
• Adult-oriented (sexual) toys
A literary work may not describe the use of adult-oriented sexual toys such as dildos, strap-ons, vibrators and similar 'adult toys'. This prohibition extends fully to other household objects or food objects used in sexual acts or for a sexual purpose.
A literary work which presents fictional characters under the age of eighteen in a sexually-suggestive manner or which depicts children or underage teenagers engaged in sexually oriented acts will be immediately classified as child pornography and removed by the reviewing staff.
In cases involving established characters under the age of eighteen taken from popular entertainment, fan fiction involving sexual relations of any type will be prohibited for these characters without exception.