A shot of gin, with a small hint of Lea & Perrins. Consumed in one go. Can also be a 'shit finger' when using tabasco sauce.
Origins of first invention trace back to the 'Nutshell' pub, in Bury St Edmunds, Suffolk of England. The pub is one of the smallest in the UK.
"Shut up Jamel you nigger, and take a poo finger"
"Can I please have £20s worth of shit fingers, then hand them round the bar to all these old people reading papers"