A method of bonding a connector to a first object , comprising: - providing the first object with a first opening , the first opening being a through opening; - providing the connector , the connector being separate from the first object, the connector comprising a thermoplastic material and body of a material that is not liquefiable or liquefiable only at substantially higher temperatures than the thermoplastic material; - arranging the first object and the connector relative to one another so that the connector reaches from a proximal side through the first opening ; - using a source of mechanical vibrations to generate vibrations, and applying the vibrations and mechanical pressure to the connector until, under the effect of the vibrations and the pressure, a flow portion of the thermoplastic material is liquefied and caused to flow sideways radially into an open space; and - removing the source of the vibrations and causing the liquefied thermoplastic material to re-solidify; - wherein after the step of removing, the connector comprises a foot portion , a head portion , and a shaft portion between the foot portion and the head portion, the shaft portion extending along an axis through the first opening, and thereby securing the connector to the first object; - and wherein the flow portion forms at least a part of the foot portion or the head portion or both, the foot portion and the head portion; - characterized in that the body has at least one locking feature on a lateral surface, which locking feature cooperates with the thermoplastic material to stabilize the relative position of the body within the embedding thermoplastic material. - providing the first object with a first opening , the first opening being a through opening; - providing the connector , the connector being separate from the first object, the connector comprising a thermoplastic material and body of a material that is not liquefiable or liquefiable only at substantially higher temperatures than the thermoplastic material; - arranging the first object and the connector relative to one another so that the connector reaches from a proximal side through the first opening ; - using a source of mechanical vibrations to generate vibrations, and applying the vibrations and mechanical pressure to the connector until, under the effect of the vibrations and the pressure, a flow portion of the thermoplastic material is liquefied and caused to flow sideways radially into an open space; and - removing the source of the vibrations and causing the liquefied thermoplastic material to re-solidify; - wherein after the step of removing, the connector comprises a foot portion , a head portion , and a shaft portion between the foot portion and the head portion, the shaft portion extending along an axis through the first opening, and thereby securing the connector to the first object; - and wherein the flow portion forms at least a part of the foot portion or the head portion or both, the foot portion and the head portion; - characterized in that the body has at least one locking feature on a lateral surface, which locking feature cooperates with the thermoplastic material to stabilize the relative position of the body within the embedding thermoplastic material. <EOS>