You may find it more convenient to purchase an enema bag on the web. Just do a search on "enema bag" and you'll find a number of places that sell them. Most national pharmacy chains have them for sale on their web sites.
It's a good idea to have an enema bag even if you don't plan on using it now.If you ever decide you need to go right away, relief is only minutes away. And I wouldn't worry about stirring up the wastes in the colon, it's a lot less healthy to let the waste matter stagnate inside your colon. You can always take a follow up enema afterwards and the results of that will help you determine how effective the first enema was.
The image below is from walgreens.com.
For more information about how to give yourself an enema see the following links: