I don’t think that the person who started this conversation posted good sources, and I also get a distinct air of transphobia from them. But it is just true that the ‘cotton ceiling’ refers to the concept that some—I repeat, some—trans women think cis women are in some sense politically obligated to sleep with them.…

Yes, yes they are. This is what the cotton ceiling means. This is all that it means. I know a good many trans women find the concept disgusting, but I have seen it used by a great number of people. I honestly find the concept disgusting, and have been astonished to see it bandied about by trans activists.