How can I pray and deal with the irregular, very slight discharge of stool, knowing that it stops immediately after ghusl and wudu'? Is it permissible to perform wudu' once for all prayers, relying on the rule of pardon for slight impurities? And does the nullification of wudu' by wind require washing the anus?

If the discharge occurs twice a day, the person is not considered to have incontinence. Rather, its emission nullifies ablution, and ablution must be renewed if it appears thereafter, due to sufficient time for purification and prayer. As for the impurity of the discharge, the majority of scholars believe it must be removed, while Maliki jurists are more lenient in this regard. The safer approach is to remove it by pouring water over the defiled spot until the impurity is gone.