Green’s Dictionary of Slang

flutter v.¹

to have sexual intercourse.

1890–1904

Farmer & Henley Sl. and Its Analogues III 40/2: Flutter [...] (common) To go in for a bout of pleasure.

In phrases

flutter a judy (v.)

to pursue and/or seduce a woman.

1890–1904

Farmer & Henley Sl. and Its Analogues III 40/2: to flutter a judy = both to pursue and possess a girl.

SE in slang uses

In phrases

flutter a skirt (v.)

to work as a prostitute.

1890–1904

Farmer & Henley Sl. and Its Analogues.