It’s called post-micturition convulsion syndrome. It’s experienced by most men and about 50% of women, but there has apparently been no actual scientific research into it.
I guess… and I never thought I’d be saying this, but… maybe I need to watch more men pee. What shiver? I shake (the plumbing) because my plumbing is 56 years old and the valves aren’t perfect and I hate walking out of the bathroom with a wet spot in the front of my pants. But all of my shaking is deliberate. (And there’s not a whole lotta shaking going on in that regard, anyway.)
Heat-loss. Mini-orgasm. Parasympathetic nervous system shaking you automatically so you can rid yourself of droplets.
I think the heat-loss may actually hold some water no pun intended. Since I tend to experience a similar thing occasionally during defecation, as well as urination. I must take note next time I vomit, if it happens there too then I need to sell my story.
Wow, I didn’t know men did that. I knew when my son was a baby he did that and I thought it was cute. I didn’t know he might still do that. Well, interesting, must investigate this further.