Hi,
Welcome to the discussion board. Actually, the lower right quadrant (the ascending colon, cecum, and terminal ileum) is the area where MC is typically most active, so it's somewhat common for that to be a center of pain associated with MC.
I'm not a medical professional, but as far as I am aware, an intussusception in the rectum would seem to be very unlikely. I would think that physical extension issues of that type in that section of the colon would normally present as a prolapse, rather than as an internal intussusception. In addition, an intussuscepton of the colon (in an adult) would be very uncommon — it typically involves the small intestine (usually the ileum), not the colon. We have at least one member who does have an intussucceptoin. You might be interested in some of her posts in the threads at the following links:
http://www.perskyfarms.com/phpBB2/viewtopic.php?t=17612
http://www.perskyfarms.com/phpBB2/viewtopic.php?t=18099
http://www.perskyfarms.com/phpBB2/viewtopic.php?t=18239
However, in your case, it appears to be very unlikely that you have an intussusception. Instead, it's very likely that you are simply dealing with an MC flare. One thing to consider is that MC can present as either diarrhea (D), constipation (C), normal bowel movements (N), alternating D and C, or just about any other combination of those symptoms. When MC is active, it's very common for stools to have a "ribbon" appearance, due to inflammation in the rectum. I've had that same experience myself, many times, back when I was reacting, and so have many other members here. My own symptoms alternated between D and C.
Are you restricting fiber in your diet? Fiber in the diet is contraindicated for MC (it perpetuates the inflammation), and fiber can lead to ribbon-like stools, staining, etc., because it can contribute to swelling in the rectal area. Hemorrhoids are also closely-associated with active MC, and they commonly cause ribbon-like stools and very uncomfortable defecation, due to the constriction which causes straining and pain.
The bottom line is, I'm not a doctor, but IMO the odds are very high that you do not have an intussusception. Instead, you're dealing with some of the same symptoms that many of us here have had to deal with when our MC was active. If you are seriously concerned about it though, you should check with your doctor to see if any tests are warranted.
Again, welcome aboard, and please feel free to ask anything.
Tex