If you are constipated, I'd suggest that you start with a mild soap solution enema instead of vinegar. Mix a bar of Ivory soap in a bowl or pitcher of water at 103 degrees F until it is milky in color (don't use liquid soap unless it is in pre-measured castile enema soap packets).
Afterwards you can take a salt water solution enema to rinse out any soap residue if you wish by using a teaspoon of Sea Salt or non-iodized table salt for each pint of water, or 4 teaspoons for a full bag.