Thanks for posting your issue.
The problem could be because you are not well calculating the attack distance: there is a certain distance to attack the enemies with the tail attack.
This attack can also hit the head of a Boss without being damaged.
In addition to the tail attack, the player is able to stomp on the enemy too.
Finally, remember that Furwind has a stamina bar. If he's exhausted (by attacking too much) the player should wait a while until it is filled enough to re-attack.