Fuck another bag

When you're just simply done, your mental recourses are scarce and you have to resort to infact, fucking another bag

(As seen in the college humour Precious Plum)

The new age saying of 'the last straw' or 'for fucks sake'

When you're simply out of bags to fuck, the expression fuck another bag comes into play. Contemporary version of 'for fucks sake' or 'well I'll be dammed '.