How is “mix in” used?

In I Love You, Man (2009), one line is: “And something with sour mix in it for her.”

Which movie is “mix in” from?

The clip at the top of this page is from I Love You, Man (2009).

Phrasal verb

to add one substance to others, especially in cooking

Heard in 172 movies

mix sth in (with sth)
to add one substance to others, especially in cooking
Mix the remaining cream in with the sauce.

Definitions from the Oxford Advanced Learner's Dictionary, 9th edition

And something with sour mix in it for her.

Said in 8 films · #1