i realize you probably just wanted to start a dialogue... but consider this crazy new thing called google.
i kid you not, i came across a story about a man who used concrete in his enema recipe. needless to say, it didn't expel and he had to be hospitalized.
however, it seems there's lots of enema info - and lots of sites dedicated to the art of enema (enemii?).
but be careful! painful up inside there isn't always good... so read up.
i hope you find what you seek!