à bâtons rompus
This phrase means “without continuity,” “with frequent interruptions,” “in a disordered fashion,” “informal,” or “in an irregular way.”
The origins of this French expression are shrouded in mystery. Some believe it comes from a traditional tapestry design that contained an irregular mix of sticks or long, thin rectangular shapes.
It is more likely that this idiom comes from the military world, where beating a drum “with broken drumsticks” (the literal meaning of “bâtons rompus”) means to strike two successive beats with each drumstick, without producing a smooth, regular rhythm.
An equivalent English phrase might be “in fits and starts.”