one's own style; self-taught method
Refers to a personal, often idiosyncratic, way of doing something developed through one's own experience rather than formal training. Can carry a nuance of being unorthodox or not by the book.
His cooking is completely his own style.
I learned Japanese using my own self-taught method.
Compound of 自己 (self) and 流 (style, school, manner). The 流 suffix is commonly used to denote a particular school or style of art, thought, or technique.