Yes we are allowed to show nipples.
It's PG-13
as per the forum rules;
"We do not allow the registration for users under the age of 13. This is basically for their own protection and our need to comply with US Law
We generally use the PG-13 rating as a guideline as to what is allowed. If you don't know whether your post falls under the rating, contact a moderator immediately."
as per the MPAA;
"Nudity is restricted to PG and above, and anything that constitutes more than brief nudity will require at least a PG-13 rating."
Sounds logical, except the mods don't always work that way so;
"Discussion forum posts that contain explicit, obscene or vulgar language will be removed. "
The only way to know is to do and see what happens.