A technique for performing sensing operations in the body subcutaneously employs, in combination, the housing of an electrical stimulator such as a pacemaker or an implantable cardioverter defibrillator and an integral flap member of flexible insulative sheet material which has at least one arm projecting away therefrom to an extreme tip end. Each arm is rolled about itself from the tip end on a lateral axis transverse of the longitudinal axis of the arm into a compact unit adjacent the housing. An incision is made through the skin and a region beneath the skin enlarged to form a cavity. The compact unit is then inserted into the cavity and unrolled about the lateral axis of each arm so as to be laid flat under the skin. When positioned into a desired orientation, each flap member is sutured to the skin to maintain the desired orientation.