"on the job" means having sex? That sure ruins a useful phrase.

...and in the USA, to "knock someone up" does NOT mean to go tapping at their door.

Once I discovered the academic community didn't need many Philosophers, my life has been a series of jobs, with the longest being about 5 years in a cabinet shop, from which I retired, having new skills to provide part-time income in my declining years.

But nothing compares to a year spent as a genuine Bean Counter. (I did physical inventory in a plant that canned Pork & Beans)