The calculation of the trajectory of ones ejaculatory fluid upon discharge.
Measurement includes height, distance, viscosity, striking force, and blast radius. Exact calculations are to be made not directly after the act in question, but the day after the fact, so that one may tell his bros about said act in mild exaggeration, without himself knowing that it was less impressive than he was led to believe.
"Upon climaxing, my ejacutrajectory was epic. My splooge knocked the scrunchie right out of her hair".