The unfortunate occurrence of a bowel movement that crests the rear band of an infant or toddler's diaper, resulting in yellow, curdy staining of the child's back and clothing (and often furniture, parents, and household pets).
The act of producing a shitback
Having characteristics of shitback.
See also shitleg and shitbaby
Quick! Grab the change pad, he's shitbacking!
These diapers suck - he's all shitbacky.
jarrod: yea, ill grab the laxatives
tyler: hokay, ill be in the bathroom