Green’s Dictionary of Slang

grouse n.¹

a young woman; thus sexual intercourse.

1864

in B.I. Wiley They Who Fought Here (1959) 192: You can get a plenty of Grous [sic] here but you will get wounded nine times out of ten, not with the clap but with something worse.

In phrases

do a grouse (v.) [Lancashire dial. grouse, to have sexual intercourse]

to search for sexually complaisant women.

1937–84

Partridge DSUE (1984) 317/1: C.19.