Green’s Dictionary of Slang

tommy guns n.

also tommies
[rhy. sl. = runs, the n. (1); ult. tommy gun n.]

diarrhoea.

[UK]R. Puxley Fresh Rabbit.
[UK]B. Dark Dirty Cockney Rhy. Sl. 100: I can’t eat anything at the moment because as soon as I do I get the tommies.