If your definition of manly is cowardly, immature and incapable of handling any situation in a manner appropriate to how an adult should behave.
Funny enough, "Manly" may be the perfect adjective to describe this behavior as it relates to men, in general, today. I'm one of the lucky few to have a man in my life who is a "Man" in the best sense of the word. He is strong, chivalrous, courageous and owning of his own decisions and responsibilities. This is so very far from the norm, and I'm sure he's the last of a dying breed.
The more I see in the way of men scurrying off because they are overwhelmed by adult responsibility, sulking back into an existence that belongs to childhood, what the word "manly," may have once appropriately described, is endangered, if not extinct.
I am no feminist, quite the opposite, actually. I enjoy the old school outlook that women are the emotional creatures, and men have a strong sense of pride and dedication to their wife and family. In my life, I've seen so far only women have a sense of pride and protection, true strength and the willingness to sacrifice.
In the severe trials of life, I've watched Men weaken, fall and fail without even giving up a fight.
Sadly, in today's lack of honorable masculine nature in men, this probably is entirely appropriate "manly" behavior. An action that should seemingly belong to a boy, to a child.