The opposite of "Man up." To shy away from one's manly responsibilities.
Like the time, when you were supposed to pick up the beer for the game, and instead you spent the morning at Bed Bath & Beyond with your fiancee, and when you got to your buddy's apartment for the game they had pizza but no beer, and everyone said, "Dude, you really went man down on this one. How's about you man up and go get the beer?"
Low caliber thinking, the opposite of brain thinking like the time you and your jackass friends came up with the idea of jumping on stage at Ozzfest, mooning the crowd, and lighting your farts so it would go viral on Youtube, and it did go viral on Youtube, not because it worked, but because your asses caught fire.
Low caliber thinking that produces high caliber results. A combination of brain thinking and ass thinking. Like that time? At band camp? When you came up with the jackass idea of hiding your weed in the oregano jar in the mess hall, and they cooked spaghetti that night, and the whole camp got baked and it was awesome?
Man, I don't think I would do that if I were . . . Dude! Brass Thinking!
High caliber thinking, like the time in high school when everyone was trying to figure out whether the assistant gym teacher's breasts were real, and you came up with the idea of drilling that hole in the locker room wall, and it worked, and they weren't real, in fact they were nothing more than a padded bra, which was disappointing and destroyed everyone's adolescent fantasies, but was O.K. because your brilliant scheme actually worked.