This is what actually stands for the abbreviation S.O.S., which is either "ass on ass" or "ass of ass". When your vessel is in distress in the middle of a deep green sea, both versions are true.
Radio transmission: Our ship has lost control, we are adrift, without rudders we are sure to crush! Ass-o'-ass! Ass-o'-ass!
by Murdoc Kylburne April 13, 2020