BTW...it appears that we are both online right now by the quick turnaround time.
The "clicky thing" a term I like, is usually referred to as a "clamp." It's how you control the flow of enema solution.
Take the enema slowly. When you begin to cramp, pause for a few seconds or more. Open the clamp and take in some more. This is useful in several ways. (The longer you can retain the enema, the more effective it will be).
Even the least expensive enema bags have an effective clamp. I have a problem with the cheap plastic tubing supplied with most drugstore products, so I have upgraded considerably.
By the way...keep the clamp easily accessible. When open, they have a tendency to slide along the tubing and can soon be out of reach. That is awkward.