In the beginning, that tightness is the PC muscle resisting - this is a muscle that had never before had to yield to something, and it's had a hole cut in it. Eventually, there's also the issue of tightness with the scar tissue contracting, around month 3-4. My GP recommended at about 4 months post-op that I do a little bit of scar tissue massage before each dilation (about 2-3 minutes of gently pressing with fingertips around the ring of scar tissue at the entrance, but I'd imagine this could be adapted for wherever the scars are forming, and if it hurts you're doing it too hard).
That helped pretty much right away, and I'd say by 5 months I stopped having issues with tightness unless I'd gone too long between dilations, as in skipped at least a couple of sessions. I assume that was the PC muscle tightening up again. I never had much trouble getting to depth, though - it usually took a couple minutes at most to get everything to loosen up.
The nice thing is that we can squeeze that PC muscle on purpose, and it's the same muscle group that cis women use to bear down on a penis with their vagina. I hear guys like that. 😉
