keep in stitches
keep (one) in stitches
To continue to make one laugh hysterically or uproariously. The stand-up comic kept the audience in stitches from beginning to end. My friend Michael always gets into the wackiest adventures, and his stories never fail to keep me in stitches.
keep someone in stitches
Fig. to cause someone to laugh loud and hard, for a period of time. The comedian kept us in stitches for nearly an hour. The teacher kept the class in stitches, but the students didn't learn anything.