Can be used as a replacement for the swear word for fecal matter from the bull, or fecal matter in general, however, it is not fecal matter itself. It is, in fact, a material that is so low that it is even lower than fecal matter. It is so low that it doesn't exist, yet it is frowned upon.
It can have the suffix -tion as the act of radada. Radada may be a verb, noun or adjective, depending on its use.

to sport a boner, fly the sail at full mass, rock hard, etc.