The word orginates in a small town in Cambridgeshire England, after an instead in the local supermarket. It is said that whilst working, two shop assistants keep dropping products and makeing accidentally causeing one to say "pooh" and another to say "we fail at work today mate". One of the workers then when on to say, "we poohfail at work today"
The word is most commonly used when something fails or goes wrong.
"I've poohfailed at my course work"
"My life if such a poohfail"