A film-supporting device is used with a waste-disposal unit. The device comprises an annular body. The annular body has an annular wall. The inward radial surface of the wall defines a central opening of the body. The outline of the central opening in a transverse plane of the device has variable diametrical dimensions with a first diameter of greater dimension than the second diameter. The outline has two of the first diameter of generally equal dimension and two of the second diameter of generally equal dimension. The device has tubular film about an outward radial surface of the annular body. A free annular end is dispensed outwardly from the annular wall. The free annular end is closed to form a bag. The opening of the bag is accessible through the central opening and is of optimized shape via the central opening for the disposal of waste. A method for disposing of waste on a scooping tool is also provided.