The Collaborative International Dictionary of English v.0.48:
Sucking \Suck"ing\, a.
Drawing milk from the mother or dam; hence, colloquially,
young, inexperienced, as, a sucking infant; a sucking calf.
[1913 Webster]
I suppose you are a young barrister, sucking lawyer, or
that sort of thing. --Thackeray.
[1913 Webster]
Sucking bottle, a feeding bottle. See under Bottle.
Sucking fish (Zool.), the remora. See Remora. --Baird.
Sucking pump, a suction pump. See under Suction.
Sucking stomach (Zool.), the muscular first stomach of
certain insects and other invertebrates which suck liquid
food.
[1913 Webster]