Wordorigins.org

This is a slang phrase with many variants. The verb is usually either hawk or hock and the subject varies between loogie, louie, and lunger. It means to cough up phlegm and dates to the 1970s.

Hawk is an old verb meaning to clear the throat or cough up phlegm. It dates to the late 16th century and is probably echoic in origin. From Richard Mulcaster’s 1581 Positions:

For hauking vp of blood.

And from Richard Stanyhurst’s 1582 Æneis Translated:

In such hauking wise, as if he were throtled with the chincoughe.

Hock is a variant of the original hawk.

Regarding the second half of the phrase, lunger appears to be the original. That word has meant a gob of phlegm since 1946, and a tuberculosis patient since the 1890s. From Kate Sanborn’s 1893 A Truthful Woman In Southern California:

The rainy season is hard for “lungers” and nervous invalids.

From Mezzrow & Wolfe’s 1946 Really Blues:

Tell him to cough up a lunger.

The variant louie dates to c.1970, when it is glossed in that winter’s edition of Current Slang:

Hang a louie, v. To spit on someone.—College students, both sexes, Minnesota.

Loogie is recorded as early as 1985 (although I recall it from my high school days some years earlier than this) in the San Francisco Chronicle of 27 April of that year:

In the middle of a French kiss, she slips a killer loogie into his face.

(Source: Oxford English Dictionary, 2nd Edition; Historical Dictionary of American Slang; Proquest Newspapers)