Child: But Mom... I don't want to mow the yard!
Mom: Well, tough titty. You're going to do it anyway.

This Jazz Cabbage got me zooted. Jazz Cabbage is less harmful than Squares. I’m smoking that Jazz Cabbage boy.

a: i got shot blood
b: tough titties

friend: "my bf cheated on me"

you: "didnt you cheat on him last year"

friend: "yeah but..." (you cut her off)

you: "tough titty bitch"

You got a D on your math quiz? Tough titty.

Ma Sheila's famous comment when Ian Leslie on ?60 Minutes,told her that 'We', the Australian people in the town in Western Australia near where there was a commune of 'Orange People', did not want the Orange People there. She replied, "What can I say. Tough titties"
The previously current expression that I think she was trying to quote was, "Tough Bikkies".
Her reply largely took over from that.

I would never say, "It's just tough titty."
Usually this phrase occurs alone, as a clever retort.