Signature images should not have nudity. They should also not be visual representations of sex in progress.

You may include links in your signature, but not to pornographic or unsuitable websites. If you do include such links, you'll get a warning, and if you don't fix the issue, you'll lose your signature privileges in this forum, which could include your HTML posting privileges too.

If you use an artist's graphic or picture for your signature, character graphic, or something else, if at all possible, be sure you get their permission and give them proper credit.

Copyright violating material will be deleted at the request of it's true owner.

This game is at least partially public.

People under 18, we call them kids, might wander through it.

That being said, put some clothes on.

Another note on signatures:
Keep signatures reasonable. If a person has to scroll in any direction, it's too big.

General rule of thumb is nothing over 400x400px and you should be good to go. This includes groupings. The entire group shouldn't be over these sizes. :)