Today I discovered that the iPlay swim trunks with built in diaper really do work. All of the poo stays in! At least until you decide to take them off, at which point one may find herself wrestling with a wet baby in the shower, desperately trying to peal the tight shorts off without poo falling to the ground.
This is impossible. Poo will go everywhere, and then you just hope and pray that no one steps in the poo. But someone will - probably both people - and then you'll be cursing those swim diapers while madly trying to clean up the baby and scooping up poop.