The dolly tub was used for washing clothes before the introduction of the washing machine. My mother used one until quite recently for washing large items such as blankets.
It was a large galvanized steel tub, originally wooden and the washing inside was 'mashed' using a metal plunger on a long handle, earlier ones would have been made of wood, resembling a small three legged stool on a stick.
This plunger is usually called a dolly peg in books and folk museums but in Gloucestershire it was called a 'posher' and it seems to have various names in different parts of the country.
I had assumed that posher was Gloucestershire dialect for pusher but I have recently a similar name used in Northumbrland, I think it was 'posser'.
Any other variations or explanations of the etymology?
The dolly peg was also called a 'posher' in Yorkshire - at any rate, that's what my Yorkshire mother-in-law, who used one for many years in her dolly tub before she got a washing machine in 1949, called it.