anal sac has a small opening to the side of the anus that can be
identified. In this picture, some of the sac contents are being
expressed out the opening (black arrow). To completely empty the
sac, gently squeeze the sac between the finger in the rectum and the
thumb externally. Begin at the bottom of the sac and squeeze towards
the sac opening. If the contents of the sac do not express easily,
professional help should be sought.