A phrase meant to convey proof of the fact that a form of sexual congress with a woman was so recently enjoyed as to leave a lingering scent upon the man's "active" fingers. See fingering.
Generally accompanied by a hand gesture consisting of the index and middle fingers of one hand extended together and held out under someone's nose.
"I smell baby shit" is a derogatory insult meant for anybody who whines about anything. It is a reference to a baby crying when it needs its diaper changed.
Tom: "Why can't this place ever get the foam on my coffee just right? I wish the cups were a different color too!"