As Nick Z points out... "They have some very specific guidelines on the type of content allowed."

From the DeviantArt site:
"When we mention 'pornographic content' in our policies we are specifically referring to specific subjects which we will clarify below.

We apologize if the descriptions below are slightly graphic.

The following contents are considered unacceptable for submission in either visual art or literature form and will be subjected to immediate removal without notice.

• Masturbation
Hands should not come into contact with genitalia in a manner which is clearly a display of fondling or masturbation.

• Sexual Intercourse.
Subjects should not be depicted in a clear display of sexual intercourse. This includes depictions of sexual penetration, oral to genital contact, genital to anal contact, and oral to anal contact without exception. Some depictions of same sex genital to genital contact and some depictions of oral to breast contact might qualify under this guideline as adjudicated by staff but not all will be considered an automatic violation of policy.

• Sexual body fluids (actual or simulated).
There should be no depiction of semen or vaginal lubricants.

• Erections.
Male subjects may not be depicted with an erection."

I really enjoy visiting the Freethinker website, but this piece smacks of sensationalism...
Let's keep it relevant.