Technically, you can smoke a cigar backwards, but it is not recommended as it will result in a harsh and unpleasant smoking experience.
Cigars are designed to be smoked in a specific direction, with the closed end or foot being lit and the open end or head being drawn from. Smoking a cigar backwards would mean lighting the open end, which would result in a harsh and bitter taste as the smoke would pass over the unlit tobacco at the foot of the cigar. Additionally, the draw would be difficult as the air would not flow properly through the cigar.
Therefore, it's best to smoke a cigar in the proper direction to enjoy its intended flavors and avoid any unpleasant taste or burn issues.