making a tail
excreting, crapping, defecating, pinching a loaf, dropping a load, taking a shit, doing a george, grunting a growler, saluting the throne, taking a dump.
As Sammy realized that his whole life was coming out of his smartest orifice after days of painful constipation; he screamed with relief, "Heavens to Betsy" and slowly turned and smiled to watch himself making a tail.
make heads or tails
To not be able to choose from two things
I can't make heads or tails from this white candy or this yellow candy.