burst into laughter
break out laughing
crack up

He didn't want her cracking up in the middle of the Season.

Actually, a lot of the time, they were cracking up.

But, of course, even we crack up when the pressure is too great.

You might get it off the ground, but you'd be sure to crack up.

I do not want them to see us cracking up.

Being physical is not all it's cracked up to be.

Being number one is not all it's cracked up to be.

But I need to get through this without cracking up.

They were all close to cracking up, if he was any example.