A trachea shave is one of the most common surgical procedures for transsexuals. The surgeon reduces the cartilage in the throat to make the shape more feminine.
Many women do it in conjunction with other procedures.
If you feel your throat, you will feel several horizontal ridges of cartilage on your trachea. If you feel the prominent part, you'll feel a V-shaped protrusion of cartilage. That's what they reduce. The surgeon makes a horizontal incision in a crease of skin on the throat. Then the vertical muscles in the throat are separated to expose the cartilage.