You can convert your toilet to a very effective enema chair....actually a colonic chair.
You need to measure the distance across the rim (left to right)and outside to outside.
Cut a piece of 1/8" thick aluminum which is about 3"inches wide about 4 or so inches longer than your rim to rim measurement.
Now, drill a hole in the center of the piece of aluminum you just cut (center lenght and width) about the size of your enema tubing...it should be a very tight fit and may require a bit of lube to push the tubing thru.
Your are going to bend the aluminum at right angles near each end of the piece of aluminum. You should be able to insert the bent aluminum inside the toilet bowl rims. Now, you need to make a final bend on each side so that the aluminum ends sit on the toilet bowl rim. You now have a stable support piece to insert you enema tubing thru and then attach a long nozzle such that when you sit on the toilet seat, the enema tube goes into your rectum about 3 inches and is impossible to push out.
Finally, find a 5 gallon bucket (ie Home Depot) and drill a hole in the side near the bottom of the bucket. The hole size should allow you to insert a given diameter of a metal spigot with a barbed end which fits your enema hose. Once the round end of the spigot is inserted in the hole, you can use silicone gel to make a waterproof seal around the spigot....be sure to use lots of sealant. Let the sealant dry for at least 24 hours.
Now attache your enema tubing to the spigot. Make the tubing long enough to allow you to hang the bucket at a height which will allow water to flow by gravity at a rate which you desire. Make sure your enema hose has a clamp.
Now, to enjoy a home colonic! Fill the bucket with water at a temp you prefer. You can add salt, soap, or any other ingredients during the filling process. Make sure your clamp is closed during the filling.
You now have almost 20 quarts of liquid to inject into your colon. Be sure to lube the tube and your anus well. Let a little water run out of the colonic system, clamp and then slowly sit on the toilet seat and guid the enema tube into your colon...do this slowly and when you are comfortably sitting on the toilet seat, release the clamp and enjoy a thorough cleansing. When the need to evacuate occurs, just let it happen. After evacuation, more water will flow in and just repeat the process until all water is out of the bucket.