Green’s Dictionary of Slang

peg v.³

to drink.

c.1865		‘Kate’s Medley’ in Fred Shaw’s Champion Comic Melodist 65: While pegging into lots of Gin.
1876		M.E. Braddon Dead Men’s Shoes II 272: Mr. Secretan is [...] not a drinking man, I hope; – not given to the pernicious practice which our modern slang calls ‘pegging’.
1883		M.E. Braddon Golden Calf 86: There is a great deal of what is called pegging – an intermittent kind of tippling which goes on all day long.
1907		Sun. Times (Perth) 7 Apr. 4/7: Nigh forgettin’ how they taste, tanglefoot and rum / Got no time for feelin’ bad, got no time to peg .
1999		Guardian G2 1 July 21: How they quaffed. How they pegged.

In compounds

pegging crib (n.) (also pegging ken)

a public house, a tavern.

1844		New Sprees of London 7: When at any of these pegging cribs and lushing kens, be careful not to allow sleep to overpower you, or, on waking, you may find that some kind friend has borrowed the contents of your pockets.
1855		Yokel’s Preceptor title page: Here will be found A Capital Show-Up of the Most Infamous Pegging Kens, Sharking Fakes, Gulping Holes, Bellowsing Rooms, Fencing Cribs, Molly Clubs, Dossing Hotels, Fleecing Holes.