Green’s Dictionary of Slang

blow (off) the loose corn(s) v.

[the image is of sex in a barn; one’s panting blows away loose corn]

to have sexual intercourse.

c.1698
17001710172017301740175017601770
1760
[UK]B.E. Dict. Canting Crew.
[UK]New Canting Dict.
[UK]Bailey Universal Etym. Eng. Dict.