The vets said they had a sponge on a stick they could sell me!!
My girl squats very low to the ground which does not help!
Anyway I waited till she was busting to go & I had a spare george forman fat drip tray, so very narrow (to fit through her legs!) As she squated I slipped it under! Then emptied into a container!
Get an empty, clean tin can, a form made of aluminium foil or maybe a plastic cup not to high to interrupt the squat. Either hold it as it is or tape it to a plant support stick, metal coat hanger that you have straightened some part of to make it more functional.
When you have a sample, either put a lid on with cling film and rubber-band or pour it in an empty glass jar.
I usually just use an old saucer, esp if dog squats low, if not u will get away with any type of container, u don't need a lot, make sure dog is on lead, so u can inconspicuously bend down slowly, as trying to follow a dog off lead is a night mare, they jsut wonder what the hell u are doing following them, and become paranoid and don't perform