Definition
To feed from an inferior source of food.
To be the youngest or most neglected child.
To be last in line.
How People Actually Use It
To get a raw deal or the short end of the stick. Derived from the behavior of barnyard pigs. The "runt" or weakest piglet is forced to nurse on the tit farthest back on the mother pig, which gives the least nourishment.
"The elderly tend to have to suck the hind tit when it comes to social services."
Source: Urban Dictionary