It ought to be quite obvious that the less force used, the better. An enema is a very delicate procedure, and should be performed with great care. The point is not to use pressure or force to clean the colon - in fact, this could end up causing damage. If you intend to perform an enema, do so very carefully and gently.
In general, it is advisable to avoid an enema unless it has been recommended by your doctor. Risks include perforation of the colon and sudden upsetting of the electrolyte balance of the body due to water absorption. The common idea that an enema helps "cleanse" toxins from the body has no scientific background. Your doctor will recommend an enema only for certain cases of severe constipation, to administer certain medications, to perform certain tests, or to clean the bowel before it is operated upon. In all these cases it is most likely that the procedure will be performed by a trained medical expert. If by any chance you are advised to perform the procedure regularly on your own, your doctor will explain to you how it needs to be done.
answered by M W