What is considered nudity/sexual content?

[YukoFurry]

Is a naked male chest allowed? What about a slightly less fit male? Where do male boobs become nudity or sexual?
I take showing female nipples is not allowed, but at what levels is it acceptable? Guidelines don't show a tollerance and the steam point shop doesn't either. How many percent of the female chest are allowed to be unclothed? How big is the cup size allowed to be? Is an unclothed female chest without nipples considered NSFW? When is a clothed female considered suggestive? What pose is considered suggestive? What facial expressions are considered suggestive and unfit?
What about the waistline, how much skin is allowed to be visible? What is the maximum allowed butt size? What angle is considered unfit?