expression, godan verb (-su)
act patronizingly; act like a big brother
Used when someone behaves in a condescending or overbearing manner, as if they were an older brother figure. Often implies an unwanted air of superiority.
See also: 風を吹かす
彼はいつも兄貴風を吹かして、私に指示を出してくる。
He always acts patronizingly and gives me orders.
先輩が後輩に兄貴風を吹かすのは、あまり良くない。
It's not good for a senior to act like a big brother toward a junior.