Ideogram the company does not tell you what they consider NSFW, but clearly genitals and female nipples are not permitted.

They have a separate AI that scans prompts for forbidden speech. The word "breast" seems forbidden, even in a prompt such as, "Her hair completely covers her breasts". But you could say, "Her hair completely covers her torso" the last time I tried.

There is another AI that scans the generated images for forbidden sights. This is where they often detect nipples. Also, a lot of my previously generated images with hair covering the woman's breasts got the Fat Cat recently. I do not know why.

Light bondage is allowed, but a whole lot of previously generated bondage images got the Fat Cat recently. I do not know exactly what those images were, having only seen them briefly weeks ago, but I had never noticed anything that seemed more objectionable than what is still allowed.

I would bet that the Ideogram developers have a switch to turn off the NSFW censors. :-)