ears back
When a character is folding their ears backwards. It can be a sign of many things; such as submission, pleasure, anger or fright.
Examples:
post #860593 post #776031 post #1517191
See also:
The following tags are aliased to this tag: ears_backs, ear_back, ears_flicked_back, ears_laid_back (learn more).
This tag implicates pivoted_ears (learn more).