The verb пахать means to plough.As in to plough land.
Its other idiomatic expression means:

1)to work
2)to tire one's ass off at work

First you can use the verb when u want to say for instance:

1) Does your email work?
Твой е-мейл пашет?

2) Yeh im workin my ass off at work damn it
Вот я пашу на работе блин

3) We're ploughing farrow land
Мы пашем под пар