I am pretty nervous about commenting on this subject as some people here are so easily offended. Nevertheless it is important information, especially for those who are planning to have srs.
After carefully and thoroughly washing your hands place one finger, or two or three, inside your mouth and feel the inside of your cheek. That is what the inside of my vagina feels like. Now, push out. That is how "stretchy" it is.
What you are feeling inside your mouth is mucousal tissue. This is now available via the peritoneal graft.
Just something l think anyone considering srs might consider.