Bisacodyl certainly increases the power of an enema.
I've tried it a couple of ways. Firstly, by crushing/grinding up 4 Dulcolax pills and dissolving them in a few ounces of warm water. In my experience, the pills never fully dissolve, even if some bicarbonate of soda is added. I guess that has been suggested because the pills are coated to pass through a person's acid stomach, undissolved. The coating dissolves in the alkaline colon, releasing the laxative chemical and making the person poo.
I really prefer the Magic Bullet suppositories. They use a base that readily dissolves in warm water within a minute or two and the solution can easily be added to a bag of warm water.
Magic Bullets are not the same as Dulcolax or generic suppositories. which use an oily base.
In water they may melt, but do not dissolve.
One Magic Bullet is supposed to be the same as two 5mg pills.
My preference is to use only one suppository in 1000ml to 1500ml of warm water. For me, that produces a very strong evacuation, but doesn't have to be given so quickly as to cause pain.
Make the solution too strong and you will start to poo before all the solution is taken.
If you like intense cramping, this is worth a try. Get a Fleet (or generic) Mineral Oil Enema and put it in warm water to heat the oil. Drop one or two Dulcolax suppositories into the warm oil and allow then to melt completely. Then administer in the knee-chest position preferably.
The urge will build rapidly, usually without letup, and the lubricated poo is pretty much impossible to hold long. This enema causes messy accidents.
Have fun