An arrowhead is one reason that an arrow moves up and then down with the force of gravity, leading with the tip. The sides of older arrowheads that were fashioned from flint rock (「wavy stone」) also resembled the wavy lines of a rolled foreskin with the tapered tip of the glans emerging from the hemp threads binding the arrowhead to the front of the shaft, and this imagery continues the Chinese metaphor of a penis as one's arrow, or an arrow as one's penis if you prefer.
Why on Earth anyone would attach a weight to an arrow with a cord anywhere other than the arrowhead? Attaching a stone or weight behind an arrow with a long but lightweight silk cord is a historical technique primarily used for entangling targets (such as birds or running game) or for line-carrying (such as fishing or bridging gaps). In various traditional hunting practices, archers targeted fast-moving flocking birds or small running animals where a direct hit with a narrow arrow might miss or fail to stop the animal instantly. When the arrow hits or passes close to the target, the trailing cord and attached stone wrap around the animal's legs, wings, or neck, functioning similarly to a thrown bola, using the momentum of the projectile to hobble or bring down the creature by fouling its movement. If the cord is attached securely to both the archer (or a spool) and the arrow, adding a weight or drag behind the projectile serves the specific mechanical purpose of line deployment. Shooting a bare, lightweight string from a bow can cause erratic flight because the string catches the wind or creates drag unevenly. A weighted setup helps pull the line smoothly. In specialized fishing or tactical scenarios, a cord allows the archer to retrieve the arrow and anything it struck. Historically, line-carrying arrows were used to pass ropes across barriers such as rivers, chasms, or walls. A trailing weight helps stabilize the trajectory of the cord package as it arcs through the air, ensuring the line carries far enough over the target obstacle without tangling. Note however that this glyph contains no elements of either a bow or an arrow, so originally it may have referred to something completely different.
Perhaps from the「fluids flowing on prepuce, down to the stones」as the whole schmear as it were. Frankly, all these possible elements combined once again seem to indicate a long tapered shaft with a sharp tip deliberately inserted into flesh for the purpose of restoring a flow of fluids, a tool known as a bougie, or perhaps in this case to dislodge a「stone at the dirk tip」of a patient passing a kidney stone.

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Japanese EDRDG: arrowhead, stone tied to an arrow shaft
Unihan extended: arrow-tip