Green’s Dictionary of Slang

drizzlies, the n.

(US) diarrhoea.

1962		R. Tregaskis Vietnam Diary 155: I only got the drizzlies when I got back because the food seemed rich.
1973		C. Cussler Mediterranean Caper/Mayday! (1985) 180: Ever since breakfast I’ve had the worst case of bowel drizzlies in my life and I’ve barfed twice.