An instrument with a two-part plunger for subcutaneous implantation is provided. An incising body defines a non-circular coaxial bore and includes a cutting edge formed on a distal end. A two-part plunger is non-fixedly contained within the coaxial bore and includes a tongue blade assembly and a plunger assembly. The tongue blade assembly is provided on a bottom surface of the coaxial bore and includes a tongue blade shaft and a thin tongue blade with a sharpened clearing edge on a distal end. The tongue blade assembly has a length exceeding the coaxial bore. The plunger assembly has a length exceeding the coaxial bore and includes a plunger shaft and a plunger affixed on a distal end. The plunger is slidably positioned on a top surface of the tongue blade.
