1.
If something doubles you up, or if you ~, you bend your body quickly or violently, for example because you are laughing a lot or because you are feeling a lot of pain.
...a savage blow in the crutch which doubled him up...
They laugh so hard they ~ with laughter.
PHRASAL VERB: V n P, V P with/in n
double over
Double over means the same as ~ .
Everyone was doubled over in laughter.
PHRASAL VERB: V-ed P
2.
see also double 11