Filter by string column as a substring of another string

I am trying to filter a dataframe by a string column. I would like the filter to return all rows where this string column is a substring of another string. Any searching I do for this problem leads to results about the converse – filtering a dataframe where a string columns contains a substring.

In other words, what I am attempting to achieve is:

df[df["string_column"] in "some_string"]

or

df[df["string_column"].str.is_substring_of("some_string")]

not

df[df["string_column"].str.contains("some_string")]