I can't remember the exact term but it is like a low fibre diet - a low emissions diet? Nothing that will cause wind or irritation (wholemeal wheat, bran, pulses, etc.) It is quite restrictive. I basically lived on white bread, fish and stuff like that. Boring but it did help.
I took my enema at the hospital. I made sure I was at least fifteen minutes early. Easu to apply, snap, shove, squeeze (trousers and pants down first of course!!!) :) The reason I say that is that when it kicks in you may need several visits to the loo before it settles down and you do not want to have the runs on the bench!
I nearly did wet the bench one day as things got delayed after my drink, so keep an eye on drink timing too.
Good luck.
PP