Green’s Dictionary of Slang

1. the penis [20C+ use is US; note robin is the pet name for a servant’s penis in the late 19C pornographic classic The Modern Eveline (the heroine’s incestuous brother is named Percy)].

a.1661		‘The Rebells Reign’ in Rump Poems and Songs (1662) i 315: Men were never so spic’d with the Sceptre of Christ / In the hands of a Saint in grain. / ’Twas brewed in their Hives by Citizens wives, / Who ventured their husbands far, / With Robin the fool, there was ne’re such a tool / To lead in the womens War.
c.1707		‘A Shepherd Kept Sheep’ in Farmer Merry Songs and Ballads (1897) IV 123: I prithee now tell me what is thy Name, fa, la, la, / Why Robin in the Rushes my Name is, quoth he.
1719		in D’Urfey Pills to Purge Melancholy V 36: Then for Robin in the Rushes, she did enquire [...] But he hung down his Head, and he would not come nigh her, [...] He wink’d with one Eye, as if he had been Blind.
c.1800		‘Song No. 16’ Papers of Francis Place (1819) n.p.: She had rosy cheeks and a dimpled chin / And a hole to put poor Robin in.
1848		Boston Blade 8 July n.p.: The South End robins should not spread their wings over those North End shad — it is against the laws of Nature for birds and fish to amalgamate.
1890–1904		Farmer & Henley Sl. and Its Analogues.
1956		H. Gold Man Who Was Not With It (1965) 5: I don’t booze, I don’t mainline, I hardly even pull my robin.
1992		(con. 1920–57) Randolph & Legman Ozark Folksongs and Folklore II 787: Other common names for the male organ are [...] rhubarb, robin, stalk, [etc.].

2. a child beggar, ‘standing about like a starving robin’ (Ware) [a philanthropic clergyman, the Rev. Charles Bullock, organized a series of ‘Robin dinners’, at which he fed thousands of such unfortunate children].

1899		Daily Tel. 7 Jan. in Ware (1909) 210/1: ‘Robin Dinners’ are due to the kindly suggestion of the Rev. Charles Bullock, editor of Home Words whose appeals to the generosity of his readers to enable him to entertain 25,000 or 30,000 London children every year.
1913		Derby Dly Teleg. 27 Dec. 3/4: The Derby ‘Robin’ Dinners [...] The society [...] was founded 21 years ago with the object of providing a Christmas dinner [...] for the poorest and most destitute children in town .

3. a penny [ety. unknown; perhaps mis-definition: the robin was engraved on a farthing rather than a penny].

1894

Chatham and Rochester News 20 Jan. 7, 5: Witness asked him how much he got, and he said, ‘Seventeen and a robin’ [F&H].