A method for constructing an instrument with a two-part plunger for subcutaneous implantation is provided. An incising body is formed by defining a non-circular coaxial bore and sharpening a distal bottom edge. A two-part plunger including a tongue blade assembly and a plunger assembly is constructed. The tongue blade assembly is constructed by sharpening a beveled end of a flat thin tongue blade and by affixing a straight tongue blade shaft to an end of the tongue blade opposite the beveled end. The tongue blade assembly has a length exceeding the coaxial bore. The plunger assembly is constructed by affixing a plunger to a plunger shaft on a distal end. The plunger assembly has a length exceeding the coaxial bore and is oriented adjacent to the tongue blade assembly. The two-part plunger is inserted through an end of the incising body.
