That's a tough act to follow

Tough titties.

This steak is as tough as leather 

Times are tough.

That was a tough pill to swallow

He's one tough hombre

That's a tough nut to crack

Tough luck 

You will just have to tough it out

When the going gets tough, the tough get going 

Oh a tough guy huh

I’m in a tough spot

She's as tough as nails.

It's a tough egg to crack

He's a crack head

You crack me up

Would it hurt to crack a smile 

How did that fall through the cracks

Step on a crack break your mommas back.....

We left at the crack of dawn

You've got plumbers crack

You need to crack a few eggs to make an omelette 

That's a bad egg to swallow

You are a bad egg 

Go suck an egg