Male die, forming die and forming method

The male die comprises an inner male die body and an outer male die body, the outer male die body is used for being arranged on the inner male die body in a sleeving mode, the outer male die body is provided with a through hole allowing the inner male die body to penetrate through, and the outer male die body and the inner male die body can move relatively, so that the inner male die body can be switched from the initial state that the inner male die body shrinks inwards relative to the outer male die body to the forming state that the inner male die body stretches into the through hole; when the inner male die extends into the through hole, the outer surface, provided with the through hole, of the outer male die and the outer surface of the part, extending into the through hole, of the inner male die are spliced to form an arc-surface convex part, the arc-surface convex part is matched with the shape, needing to be formed, of to-be-formed glass, and the inner male die is provided with a first suction part us