1‘his whole body convulsed’
shake uncontrollably, shake violently, go into spasms, shudder, jerk, thrash about
suffer a fit
laugh uproariously, roar with laughter, hold one's sides, be doubled up with laughter
split one's sides, be rolling in the aisles, be in stitches, die laughing, laugh like a drain, bust a gut, break up
be creased up, fall about laughing
We take a look at several popular, though confusing, punctuation marks.