A method of bonding a second object to a first object includes: providing the first object having a thermoplastic liquefiable material in a solid state; providing the second object having a surface portion that has a coupling structure with an undercut, so that the second object is capable of making a positive-fit connection with the first object; pressing the second object against the first object with a tool that is in physical contact with a coupling-in structure of the second object while mechanical vibrations are coupled into the tool; continuing to press and couple vibrations into the tool until a flow portion of the thermoplastic material of the first object is liquefied and flows into the coupling structures of the second object; and letting the thermoplastic material re-solidify to yield a positive-fit connection between the first and second objects by the re-solidified flow portion interpenetrating the coupling structures.