All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
It is reported that the Prophet prohibited sitting in the position of Habwah, which is the posture of sitting with the legs and thighs contracted towards the belly, the back bent forwards, and supported in that position by the arms crossed over the knees.
Some jurists interpreted the text to mean dislikeability and not prohibition, because it was reported that some of the companions used to sit in this position. Moreover, some scholars stated that the wisdom for the dislikeability is that this position inclines a person to sleepiness which leads to invalidating his ablution.
Allaah Knows best.