1. Measure a rough baseline — or skip the clock
For two or three sessions, note the time from starting stimulation to the start of ejaculation. Keep the window consistent (stimulation begins → ejaculation begins, pauses not counted) and take the range, not an average. Two or three readings are rough data — that's expected, and it's enough. The number is a reference point for your own trend, not a verdict.
If clock-watching winds you up, don't time it: mark each session high / medium / low by feel, or count breaths. Anxious monitoring isn't a neutral measuring tool — in one lab experiment, adding a distraction task suppressed physical arousal, and self-critical self-monitoring during sex is linked to difficulties. A noisier baseline you can live with beats a precise one that wrecks the practice.