Wash first and after because you eat this with your hands.
To make ẹbà, gari flour (which should be further pounded or ground if not already 'fine') is mixed into hot water and stirred well with a large wooden spoon until it becomes like a firm dough, firmer than, say, mashed potatoes, so it can be rolled into a ball and can keep its shape.
To eat, a small amount of ẹbà is taken with the fingers and rolled into a small ball and dipped into the obe (a thick soup) such as okra soup, bitter leaf (ewurò) soup or pepper soup (ọbẹ ata or efo depending on dialect) with either okro, ogbono (Igbo)/apon (Yorùbá), or ewédú, meat or fish, stewed vegetables or other sauces such as gbegiri or egusi soup (melon).
Ẹbà is made from dried grated cassava. It can either come as yellow or an offshade of white. The yellow garri is often eaten by the Igbo tribe of Nigeria. It is made from mixing dried grated cassava with palmoil. Gari is very rich in starch and carbohydrate. It is quite heavy as a meal and a staple food of the western Nigerians. It is often eaten with richly made soups and stews, with beef, stockfish or mutton depending on personal taste. (http://en.wikipedia.org/wiki/Eba)