A plugging method allowing plugging an orifice with a central axis (XX') pierced in a wall, such as a casing wall, by means of a plug having a threaded hub provided with at least one thread, said method comprising: - a screwing step (a) during which the threaded hub of the plug is screwed into the orifice by fitting the thread of said hub against the wall, in a direction called « penetration direction », against an elastic member (9, 31) which exerts on said hub a biasing force oriented in an opposite direction, called « extraction direction », such that said elastic member (9, 31) tends to urge the thread of the hub so as to bear at the rear against the wall, and the screwing is continued until the hub reaches a desired axial position, called « calibration position », in which the thread of the hub is pressed so as to bear at the rear against the wall by the elastic member (9, 31) - then a rotational locking step (b), during which the rotation of the threaded hub about the central axis (XX') is blocked in order to resist the screwing and unscrewing of the plug, said method being characterized in that, at said rotational locking step (b), a portion of the plug made of a thermoplastic material is heated up so as to soften said thermoplastic material, the softened thermoplastic material is forced to penetrate, and then to solidify, into a female cavity drilled in the wall of the orifice in order to constitute a male member which nests into said female cavity, the female cavity being arranged such that it forms against the male member a guide stop which, on the one hand, prevents the rotation of the male member, and therefore of the hub, about the central axis (XX'), so as to resist a screwing or unscrewing rotational movement of the plug, but which on the other hand keeps a degree of freedom in axial translation, along said central axis (XX'), of said male member within said female cavity, so as not to hinder a sliding of the hub and of its thread along the central axis (XX'), against the wall, in that there is provided, in the wall, a female cavity formed by at least one notch which opens onto the orifice and which is delimited in azimuth around the central axis (XX') by surfaces, called bearing surfaces (10A, 10B), which are substantially parallel to said central axis (XX'), and in that, at the rotational locking step (b), the softened thermoplastic material is pushed radially into said notch so as to form at least one lug which forms a male member projecting radially with respect to the hub and which slidably bears against said bearing surfaces (10A, 10B), so as to be blocked in rotation about the central axis (XX') but free to axially slide along the central axis (XX'), at the rotational locking step (b), a forming tool which exerts an insertion force in the penetration direction is applied on the plug, to soften and push the thermoplastic material into the female cavity, said insertion force thus tending to peel off the thread of the hub from its back bearing, and to displace the plug in the penetration direction relative to the calibration position, and then in that, once the male member is formed, the forming tool is removed so as to release the insertion force and to enable the hub and the male member to perform, under the action of the elastic member (9, 31), a return movement in the extraction direction, until the plug recovers its initial calibration position, with the thread of the hub pressed so as to bear at the rear against the wall. - a screwing step (a) during which the threaded hub of the plug is screwed into the orifice by fitting the thread of said hub against the wall, in a direction called « penetration direction », against an elastic member (9, 31) which exerts on said hub a biasing force oriented in an opposite direction, called « extraction direction », such that said elastic member (9, 31) tends to urge the thread of the hub so as to bear at the rear against the wall, and the screwing is continued until the hub reaches a desired axial position, called « calibration position », in which the thread of the hub is pressed so as to bear at the rear against the wall by the elastic member (9, 31) - then a rotational locking step (b), during which the rotation of the threaded hub about the central axis (XX') is blocked in order to resist the screwing and unscrewing of the plug,