Abstract: Hollow billet (13) in a first operation of a piercing mill (1, 2) is advanced over a piercer (10) placed on front end (5) of a piercer rod (6) and is retracted after removal of the piercer. During the advance of hollow billet (13) a lubricant is applied to the hollow billet inside wall processed immediately before by piercer (10) with the help of an inert carrier gas current through outlet openings (16, 17) on front part (14) of piercer rod (6). In this way the lubricant is distributed uniformly on the hollow billet wall in the first operation for processing in the second operation of the piercing mill and in the latter for processing in a third operation (in a reeling mill). Thus, no delay whatsoever occurs in the processing, i.e., the operations can be performed without interruption successively, and no environmental pollution by the agent occurs.