little | high-pitched | nervous | girlish

give, have, let out | collapse into, dissolve into, get ~s
We all collapsed into giggles. | Susan tends to get the giggles at the most inappropriate moments.

stifle, suppress
I just managed to stifle a giggle at the absurd idea.

hear

with a ~
‘Age before beauty!’ she said with a giggle.

~ about/at
We had quite a giggle about the new office romance.

a fit of (the) giggles

helplessly, hysterically, nervously
The children giggled hysterically.

about
They giggled about their teacher''s accident.

at
We giggled at the picture.

over
giggling over old photographs

with
The children giggled with delight.

a fit of giggling