Here is a good article that explains it. Interestingly coffee promotes the urge to poop in at least one-third of the population and tends to impact women more than men.

https://www.healthline.com/nutrition/why-does-coffee-make-you-poop#TOC_TITLE_HDR_2

Research has shown that caffeine makes the colon 60% more active than water and 23% more active than decaf coffee.