Asha, there are TONS of threads on colon tubes.
DO A SEARCH FOR "COLON TUBE"
There are MANY threads that will thoroughly answer your questions.
http://www.zity.biz/index.php?mx=forum;ox=display;topic=60482.0
http://www.zity.biz/index.php?mx=forum;ox=display;topic=113.0
http://www.zity.biz/index.php?mx=forum;ox=display;topic=56.0
http://www.zity.biz/index.php?mx=forum;ox=display;topic=1240.0
There are a dozen more.
You can do colon tube insertions until your arm is tired from inserting it 😁 or your colon or anus feels like it has had enough. There are times I fuck my self with large fat tubes for half an hour or more at a time. Okay, I admit it, I love to be butt fucked by heavy tubes (or my husband). I love the sensation of heavy tubing running around my colon.
You can do numerous colon tube enemas in a row. If you do many over a few hours, just make sure to eat or drink fluids that will replace any electrolytes. Mind you, electrolyte problems are RARE and mostly occur in people who already KNOW they have kidney or other endocrine problems.
You can hold a high/deep enema as long as any other enema.
You can insert any commercially available colon tube you feel comfortable with. It's when you start making your own like I have that you will reach limits in width/diameter due to tube flexibility and how you can manipulate your colon to let it pass through. Your colon will be wider than tubes you might use. See this guys video. http://www.eroprofile.com/m/videos/view/longdildoinassd6 You can see how his dildo passes around his colon. You can feel the colon tube also, especially if you are not obese.
You may well have difficulty passing the tube around the bends of your colon. In the thread I listed in your thread, I tell how to do a deep colon tube insertion. Trust me and others who have responded to my descriptive posts, my technique works.
If I didn't just answer your questions, hopefully others will respond to your thread.
best regards,
Sue