Not fitting neatly into either of two categories or positions.
Used other than figuratively or idiomatically: see between, two, stool.
Source: en.wiktionary.orgSometimes we feel we straddle two cultures; at other times, that we fall between two stools. Salman Rushdie
Between two stools one falls to the ground. Spanish Proverb
Between two stools you come to the ground. Dutch Proverb
Between two stools is a fall. Manx Proverb