Push-to-fit earplug with tip cavity

A method of making an earplug, the method comprising:

• covering at least a portion of a major outer surface of a core that comprises a first material with a second material that comprises an unactivated foaming agent, the core comprising a proximal end, a distal end, and wherein the major outer surface and a longitudinal axis extending from the proximal end to the distal end;
• inserting the distal end of the core and at least a portion of the second material into a mold cavity;
• and
• activating the unactivated foaming agent in the mold cavity to form a sound-attenuating body in the mold cavity that is attached to the major outer surface of the core, the sound-attenuating body comprising:
• a base and a tip, the distal end of the core disposed within the sound-attenuating body and the tip extending distally beyond the distal end of the core;
• and
• a tip cavity of the sound-attenuating body extending proximally from the tip and comprising a distal opening, the tip cavity having a volume defined by a side wall formed by the sound-attenuating body and a bottom at least partially formed by the distal end of the core,
• the tip cavity side wall comprising a plurality of protrusions extending inwardly toward the longitudinal axis.