Discussion Groups / English Usage / January 2010

Not anything I ever heard myself, but it appears to exist.

The first few words are going to vary, so you'll get more results at
Google Books by focusing only on "your feet under my table". It shows
some with a general sense of paying a visit or coming to dine, and some
from the last twenty years of which I am suspicious (in the sense of
their being more of remembered folk sayings than actual use), but these
have the dignity of some age:

=====

1917
And as long as you put your feet under my table, my son, you're to
remember that I am the head of this house."

1933
GRANDMOTHER : We used to say "You will obey me as long as you have your
feet under my table."

1948
... "Son, as long as you put your feet under my table and eat the food I
earned by the sweat of my brow, you are going to do what I tell you to
do . ...

1952
"And as long as you sleep under my roof and put your feet under my
table, I've got some say-so over you. Is that straight?"

1953
... a conviction that Father somehow is the head of the house --  "As
long as you stick your feet under my table I am boss.

====
In my house, the parental warning to an unruly teen was the other way
around -- "If you [bla bla bla], then THERE'S THE DOOR."

This was standard (proletarian)  idiom in England
at least up to 1950, meaning to join the household,
perhaps initially as a casual visitor or paying lodger.
(Cf. shortage of working men's hostels, so that
many poor housewives took in lodgers to help pay
the rent.)   If there was a pretty daughter in the
house as well, getting your feet under the table
might  lead to more besides.

I've never heard it exactly like this, but there is a BrE saying: "He's
got his feet under her table", which means that he's just about become
one of the family.  In olden days, this indicated that he was going to
marry the daughter of the family.

On 13 Jan 2010, Marius Hancu wrote

Others have explained what it means;  I'd just add that although I
don't recall hearing that particular idiom, the meaning was
immediately clear to me.

It would be the same with any expression implying that someone was
being housed by the speaker, whether or not I'd previously heard
the particular allusion or just made it up:  "living under my
roof", "putting your feet under my table", "parking your butt on my
sofa", "hanging your coat in my hallway", or "keeping your
toothbrush in my bathroom".