Male urine is very easy to get starting in chapter 2 once you find the bandit camp. Prior to chapter 2 it’s only possible by finding select events or by using piss liquors on male NPCs.
If you open the journal it should tell you what you need to do to move on in the story. Even if the story isn’t that interesting to you, a lot of areas and characters are unlocked as you move through it, so it’s probably worth doing just to have more options for the sandbox stuff.
