Both DS1 (4.8) and DS2 (2.11) are completely potty trained and have been for quite some time. However, when they do a poo, I ask that they shout me when they're finished and I go in and wipe their bottoms for them and make sure hands get washed properly.
At what age did you leave your DC to do this for themselves? DS1 could probably manage this fairly well by himself (I hope!) but I know that if I trust him to do it, DS2 will want to copy his big brother and I'm sure it will end up down his legs, up his arms, on the wall. Probably anywhere but on the paper!