Rational beings that they were, the Romans and the Greeks categorized every possible variation upon the theme of masturbation, or manual stimulation: one's own hand or fingers, another's hand, a friend's hand, an over-obliging hand, and so on.  Art and poetry were to benefit from this list.

"... (Livia) did not deign proffer her soft and plump hand
Of your whore on the left
To sharpen the desires of Augustus."  Ovid

"Friend of your pleasures, you use and ply into service your hand."  Martial