Green’s Dictionary of Slang

1. (US) to be on one’s last legs, to be struggling.

1960		(con. WWII) R. Leckie Marines! 111: I’m going to ride you so hard yer gonna think yer rear end is suckin’ wind.
1965		H. Rhodes Chosen Few (1966) 208: Sergeant Moreau’s ass is gonna suck wind payday.
1975		J. Wambaugh Choirboys (1976) 121: She’s really got him sucking wind.
1982		Eble Campus Sl. Fall 5: suck wind – to speak in class when unprepared.
1993		J. Mowry Six Out Seven (1994) 326: Sabby still suckin wind.
1994		P. Blauner Casino Moon : .
2000		C. Cook Robbers (2001) 3: Sucking wind under the onslaught of money, a stripmall gangbang straddling the Balcones Fault.

2. (US teen) a dismissive retort to someone who is showing off.

1969		H. Ellison ‘A Boy and his Dog’ in Beast that Shouted Love (1976) 206: Suck wind, asshole!
1978		R. De Christoforo Grease 113: ‘Ehey, babe, handle with care, and don’t mess the hair.’ [...] ‘Sonny, suck wind, will ya, and gimme a hug!’.

3. to show off, to boast emptily.

1977

S. Stallone Paradise Alley (1978) 40: I think ya suckin’ wind.