I remember I used to use this technique long time ago. There was a short period about 10-15 years ago when I had to live in a dorm for about a year. First I didn't even acknowledge the problem, but when it escalated to the point where I went for days without pooping, I came up with this plan. I made this rule that I would sit on the toilet for 10 minutes at a certain time of the day, every day, no matter what. The rule was that I do it every time regardless if I feel the urge or not, and always for 10 minutes. It was 10 minutes if I pooped after 2 minutes, if I barely pooped, barely not pooped or whatever. It was still not comfortable, because then I started to feel the urge at other times too, but as soon as I stopped adhering to the strict timing, things slowly stopped working again. But at least it worked. It wasn't ideal, but I managed reasonably well with minimal discomfort.