I hope this suggestion helps as it helped me a lot . I am seeing a 'Bowel specialist' at Marks hospital, in London. This recommendation came from them and they told me to sit on the toilet and to have a small foot-stool and to put your feet onto it and after a while i will feel that sensation to extract.
Because it isn't always convenient to have a foot stool, I came up with an idea and that is to - Sit on the toilet and bring your legs up as close to the toilet as possible and then raise them onto tippee toes as if you were squatting. Then i when get this feeling i lean forward slightly and rest my arms on my raised legs. This is putting you into a 'squat' position. This will work the same way and you will be surprised how much this helps. Be patient though and don't force it - as it will happen - so to speak.
Good luck x