One of my first boyfriends was a physician, who remained a friend for many years, used to cum huge and multiple times a day at always the same force and volume. He was tireless and always full.
I remember the first time he kinda warned me that he was "going to make a mess" and then forcefully showered my face, head and chest in cum. As we progressed, I became comfortable sucking him off during the days as well as in the car (he was always cleaning the steering wheel, dashboard and inside ceiling) and I finally got used to having an overflowing mouthful as I struggled to swallow it all.
He did top me, sometimes multiple times in a session, and the cum would pour out of me like a stream when finished as he would keep pumping away. In fact, his bedroom wall was covered in dry cum at a great height. He could shoot from the foot of the bed all the way to that back wall. Even as he got older he still shot voluminously. I joked that my association just with him provided the most cum received than during my entire life otherwise. May he rest in peace.