flip off, v.¹ — Green’s Dictionary of Slang

flip off v.¹

to masturbate.

1972		B. Rodgers Queens’ Vernacular 115: to masturbate [...] flip it [around, off].
2002		‘Animal Farm’ at GalleryListing.com 🌐 I’ll bet he’s still flipping himself off! Not that there’s anything wrong with masturbation, of course. It’s just better to have a partner now and then.

flip oneself off (v.)

(Aus.) to masturbate.

1955		‘No. 35’ Argot in G. Simes DAUS (1993).
1978–99		G.A. Wilkes Dict. Aus. Colloquialisms.
2002		‘Animal Farm’ at GalleryListing.com 🌐 I’ll bet he’s still flipping himself off! Not that there’s anything wrong with masturbation, of course. It’s just better to have a partner now and then.