I'd research this topic before jumping into it, since you'd be doing it to antoher person you want to make sure you are doing it correctly. (ie, I have heard that you could put alcohol (booze) into the enema bag and the person gets really drunk really fast, that is dangerous... you want to make sure you know what you are doing and what the risks are.
Isn't it great living in the world of Google... where you can find anything - -
http://www.albanypowerexchange.com/BDSMinfo/enemas.htm
Is one site that seems to have some info on enemas and how they can be used in play. (I didn't read past the first page, becuase it's definitely NOT my kink.. but hey - have fun and play safe)