I have Ulcerative Colitis (similar to IBS) plus MS, and have only recently figured out which disease is causing which problem.

What you are describing sounds like some kind of surface nerve sensation (don't know how to describe it better ), whereas the "numbness" associated to MS causes me to feel nothing what-so-ever. I can't tell if I have to go; I have no muscle control to make it happen; there is no sensation when/if it does.

For those who've had an epidural before, it is similar, but without the ability to sense the pressure and/or participate in the push, ie. even if you can't feel the push with an epidural, there is instinct to know "what" to do. With (my) MS-numbness though, there is NO sensation, and NO muscle control (things just don't work!) so I often have to rely heavily on BM stimulators.

Cherie