No - it's a slang term for the drink itself. One that unfortunately reflects one of the ingredients some brewers used to use.
You could call it a human byproduct. One that long ago was used in the cleaning of floors, in the laundry, in wool processing, in the manufacturing of Harris Tweed, even in the manufacture of gunpowder - and, rather alarmingly, to freshen breath, glaze pastries and flavour/strengthen ale.
This isn't so much 'droppings' as 'drippings'... The official name of the product was lant, but it's more commonly referred to in cruder tones.
That's it - in my time I've sampled a few beers that have made me suspect that some brewers still lant their ales. Over to you.
Just as an aside, one of my sons used to go out with the daughter of the guy who wrote and first recorded 'Sailing' - Gavin Sutherland. He and his brother (creatively known as the Sutherland Brothers - and later Sutherland Brothers and Quiver) are from this neck of the woods.