"Soft poop" refers to feces that is not firm or solid, but instead has a mushy or loose consistency.
Sentences with «soft poop»
My little has pretty soft poop still at almost 2. (thirstiesbaby.com)
If your baby is still passing soft poops, then you can likely rule constipation out. (momtricks.com)
So it makes much firmer stools and the babies can have anywhere from a nice soft poop like the breastfed baby all the way down to having teeny tiny little rabbit pellets or the things that looked like little pencils coming out. (pregnancymagazine.com)