When I'm writing, carpooling, volunteering, doing chores, running errands, and keeping appointments, I'm tending to my knitting.
No, I'm not knitting while I do all that. I confine knitting to waiting rooms, theaters, home, and circle meetings.
"Tending to one's knitting" does not mean following a complicated pattern accurately or finishing a WIP in a seemly amount of time.
It also means to pay attention to one's responsibilities.
A writer for the Baltimore Chronicle and Sentinel, covering a Bush administration official's come-uppance, notes:
"It was long since clear to many in Washington that, had George Tenet stayed home long enough to tend to his knitting – his management responsibilities – instead of eternally hobnobbing abroad with kings and other potentates, 9/11 might well have been avoided, even with an indolent president."
No comment on the content. I'm focused on the cliche.
So, tending to my knitting also means meeting a deadline, taking care of chores, starting and finishing a project on time, and sundy other obligations.
If I say I'm tending to my knitting, don't assume I have needles in hand. I may be working on something else entirely.