Colon Tubes, perhaps my favourite subject, I've enjoyed them for years.
First, you will read about them in various books and publications saying they just curl up in your rectum, bullshit! In the hands of the inexperienced that's true. The key to enjoyment is to be able to get past the internal anal sphincter, and with a little practice that's easy. The shorter ones, called rectal tubes, aren't going to get much past the sigmoid colon (or sigmoid flexure). With a colon tube you can get a lot further, but your next obstacle is the splenic flexure, and this is another place where skilled hands are needed and there is a real opportunity rupture the colon wall, so with some stiffer tubes available today that is a real issue. If you manipulate past the flexure it is pretty easy to get the tube all the way across to the hepatic flexure. For most, with conventional colon tubes, that's as far as you are going to go, but there are some very skilled that can get even further.
With the larger diameter fairly soft silicone colon tubes today you can make it past the hepatic flexure into the ascending colon all the way to the cecum. If you have had a colonoscopy the doctor performing it is going to be able to do a good job looking around the cecum, I have a set of pictures from my last colonoscopy, which is a great way to know your anatomy.
So my history goes back to the 1960's a few colon and rectal tubes found in drugstores, and not much success, never getting around the splenic flexure, then two things happened. A friend gave me a colon tube that was just right in flexibility, 38 french, it would easily make it the way across the transverse colon for both me and my play partner, she loved the feeling as it slid across, and so did I. About the same time I started going to Mildred P. Burgess in Boston for colonic irrigations, and she had a collection of tubes. One day when my colonic wasn't going well she suggested a colon tube enema, She had years of experience and gave (and I think received) great joy from working a colon tube all the way across and could work it into the ascending colon, she was so good! Nothing overtly sexual but she knew how to do everything that felt good.
In the mid '70's a newspaper and a local radio ran stories accusing her of quackery and she was shut down, then, sometime about 1982 my favorite colon tube deteriorated and was no longer viable.
So for a few years there was a dry spell in deep colon tube insertion, until I went to Grand Dames in Los Angeles, early '90s, met Valarie, and had my first transverse colon tube experience in about a decade, and I gave her a colon tube enema and was able to get the tube across for her as well. This developed into a friendship that lasted until about 2000, when she got married and moved away. I had another playmate, still friends, and event though she was a nurse she was never very good at even getting past the internal sphincter, I was able to do much better for her, but she was more into receiving than giving.
During the time I was producing enema films I had one model, who became a friend, who loved insertions as deep as they could go, we used to joke about so deep it would come out her nose, only a joke, that isn't going to happen! By the way, Bridgette is Lee, and very happy with his life.
I was always looking for the ultimate colon tube, and then I found silicone nozzles. OK, I bought one way too long, but it goes in easily all the way to the cecum, takes a but it of practice and an enema or two so there is no "poop" in the way. Yes, some of us do enjoy inserting into a full colon, and doing successive clean outs... it is doing what you enjoy.
I've also read there are no nerve endings in the colon so you can't feel where it is. It is usually a muted sensation, but I and my playmates can feel it all the way to the cecum, and we love the feeling. And you can palpitat and find it, and even see it if your belly is flat. Hotkinkyjo does some videos where you can see just where the "colon snake" is, or the hand of the young woman doing deep fisting!
OK, this is a post about colon tubes, so we'll get back on track. A comfortably large diameter, a lot of really slipper lube, and careful insertion are keys. The folks selling the tubes sell an assortment of slippery stuff to help. While you can do it yourself, it is, obviously more fun with a partner. Be certain the partner is caring and careful, you don't want to turn this into a trip to the emergency room... or worse.
So, play safely and enjoy, colon tubes can be hypersexual and the play unbelieveable. Sex with a fully inserted colon tube or snake, incredible. And, yes there are some that are just super long dildoes, they can be pushed all the way in, and, no worries, you will be able to poop them out. Just think for a minute, you might be in a crowd or a concert with somebody walking around with at colon snake inside.