When a man copes with a situation through denial, minimization, or confusion as to why the problem is a problem. Oftentimes due to fear of a problem that he cannot understand or fix.
Dave doesn't "believe" in depression or understand why some people might need extra help through therapy or medication. Rather than address the issue, he says things like "Buck up" or "Emotions are for sissies." This is how Dave mandles this situation.
Also - can be used in a derogatory fashion to indicate manly stubbornness.
Person 1: I bought 50 lbs of groceries.
Person 2: Need some help with that?
Person 1: Nah, I've got it mandled.
Person 1: *Carries ALL the groceries into their home in one trip*