I was actually shocked to realize that I was not loading my brush with enough product initially. Two things helped with that. First was to switch to a boar brush for hard triple milled soaps (which I prefer). Second was the advice from Nick Shaves on You tube to load the soap like you hate it. After I started doing that I have enough for easily 2 and most often 3 passes.

Also there's no foul with reloading the brush if you need to.

Practice makes for incremental improvement. After several months I am still learning and improving my lathering and shaving techniques. That's one of the things I love about wet shaving with a straight razor is the constant challenges it provides and the satisfaction of seeing daily improvement.

Good luck.

V/R,
Docmo