Looking on the internet deeply has found these results:

so and so is the most popular phrase on the web.

and so and so 1129,000 results on the web	so and so 1537,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
so's just bought a car. No; he never came out and said, "I left because so so from down the road is having a baby and so and and Feb 10, 2016 ... ... up to date with the latest gossip you know, so and	and language learners. See so–and–so defined for kids. So and so may refer to: So and so (or "so & so"), a placeholder name used for someone who is unspecified, unknown or whose name is forgotten. So and so (or ... Related to so and 1 : an unnamed or unspecified person, thing, or action. 2 : bastard 3. See so–and –so defined for English so: severity, reconvene, restriction, inhabited, embarkation ... 1 . a person whose name is forgotten or ignored: so so came to see me.

and so and so

1129,000 results on the web

so and so

1537,000 results on the web

More popular!

and
language learners. See so–and–so defined for kids.
So and so may refer to: So and so (or "so & so"), a placeholder name used for someone who is unspecified, unknown or whose name is forgotten. So and so (or ...
Related to so
and
1 : an unnamed or unspecified person, thing, or action. 2 : bastard 3. See so–and –so defined for English
so: severity, reconvene, restriction, inhabited, embarkation ... 1 . a person whose name is forgotten or ignored: so
so came to see me.