A cup plug insertion tool comprises a cylindrical base and a cylindrical collet extending from the base and including at least two longitudinal slots that divide the collet into at least two flexible segments adapted to flex radially inward under force, an annular groove formed adjacent the base, the annular groove adapted to allow the flexible segments to flex radially inward, further wherein, the force necessary to flex the flexible segments radially inward is tunable based on a width and depth of the annular groove, a first section defining a circumferential outer diameter and a circumferential inner diameter, a second section defining a circumferential outer diameter that is larger than the circumferential outer diameter of the first section, a tip positioned at the distal end of the collet, and a chamfer formed between the outer diameter of the first section and the tip.