systems for leaching liquid waste , particularly waste water . more particularly , a cylindrical conduit or pipe for use in leaching systems . even more particularly , a cylindrical conduit which has apertures / skimmer tabs created either during the manufacture / forming / extrusion of the conduit or by punching after the forming of the conduit . most particularly , is an apparatus and method for perforating corrugated plastic pipe or smooth walled plastic pipe while the pipe is in the process of extrusion . further and even most particularly , an actuatable perforator / skimmer tab former which may be timely acutuated to cause the perforation of the wall of pipe wherein the plastic of the portion being perforated is semi - molten as , for example during the forming of the pipe or caused to be made semi - molten after formation of the pipe such as , for example , by heating of the acuatable perforator / skimmer former thereby causing the plastic to be rolled rather than cut creating thereby a perforation and skimmer tab of predetermined and selected geometry and dimension .