How To Sit In Qadah
Salah would be valid but if possible then it is better to sit with great poise and calm the way Prophet (sws) used to do and advice others to do that way as well. In between the two prostrations ( Jalsah ), the Prophet (sws) would spread his left foot and composedly sit on it . The Prophet (sws) would sit in qadah in just the same way as in jalsah by spreading the left foot and sitting on it. The right foot would be upright ( as depicted in the image on the right ). In the last rakah of the prayer, he would sometimes sit in a manner that he would place his left hip on the floor and take out the left foot towards the right one ( as depicted in the image on the left ). ( Sources : https://sunnah.com/abudawud:730 AND https://sunnah.com/abudawud:734 AND https://sunnah.com/abudawud:731 ). Attached image depicts both these positions