A note about the enema. If you do use an enema wait a few hours after the enema to start play. The first is safety, your rectum has a mucus lining and the enema will wash it away. That lining is there to help prevent infection from any tiny cuts or tears that might occur in the rectum. if you wash that mucus away then partake in anal sex there will be tiny cuts and tears like there is for any and all sex and you won't be left with your protective layer. Secondly there isn't any way for you to know if you've expelled all the water from your rectum and you would probably be a little embarassed if some enema water leaked out during play.

If you just have a healthy BM before any play then a warm bath or shower you should be plenty clean enough.

I would suggest reading Tristan Taurmino's book "The Ultimate Guide to Anal Sex for Women".

I'm also curious what finally made you change your mind.