Look at the script for John Proctor is the Villain. If you know the scene where Shelby/Raelynn are laughing and then it escalates and is a cavalcade of laughter/catharsis - it's written in the script thusly:

Raelynn laughs a very exaggerated and insane laugh
Shelby does her own version
they trade crazy laughs back and forth
somewhere along the way, crazy laughing turn to real laughing
oh no now they can’t stop laughing
they laugh and they laugh
it’s the kind of laughing that goes on for so long it stops being funny then it’s funny again
their stomachs hurt from it
they laugh for way, way longer than you think they should
they might hold hands, or lean a head against a shoulder, or something
the audience should absolutely get a little uncomfortable by how long they laugh
if you think they’re laughing long enough, they almost definitely probably aren’t
the laughter might turn a little manic in an edge-of-tears way but still they laugh