Green’s Dictionary of Slang

mainline v.

also main
[mainline n.]
(orig. US drugs)

1. to inject narcotics directly into a vein.

[US]D. Maurer ‘Lang. of the Und. Narcotic Addict’ Pt 2 in Lang. Und. (1981) 105/2: To main-line. To inject narcotics into the vein.
[US]‘Hal Ellson’ Golden Spike 113: I’d have a whole closet full of H [...] and I’d dive into it and snort and pop and main till I dropped.
[US]T. Southern ‘The Night the Bird Blew for Doctor Warner’ in Southern (1973) 51: I won’t main-line [...] Just skin-popping.
[US]Larner & Tefferteller Addict in the Street (1966) 25: That’s when I started mainlining, when I got to be fifteen. I started mainlining like a dog.
[US]T. Southern Blue Movie (1974) 188: Don’t mainline him, for Chrissake [...] we’ll have a fucking stiff on our hands!
[US]Time 16 Mar. 17: All my friends were on heroin. I snorted a couple of times, skinned a lot, and after that I mained it.
[UK](con. 1960s) Nicholson & Smith Spend, Spend, Spend (1978) 192: He’s the worst fucking junkie [...] He’s mainlined. I’ve been in his place when there’s been blood splattered all over the place from trying to get the junk in his veins.
[US]J. Wambaugh Secrets of Harry Bright (1986) 191: All these crankers’ll tell you they toot it. Bullshit. They mainline it.
[Aus]C. Bowles G’DAY 25: A muso plays gigs and mainlines.
[Scot]I. Welsh Trainspotting 31: I reckon that he’s been daein a bit ay mainlining or shit-stabbing on the Q.T.
[Ire]P. Howard The Joy (2015) [ebook] ‘Skin-popping doesn’t agree with you,’ Duffo said [...] ‘You’d wanna mainline it next time. Put it straight into your vein’.
[US]Africa News Service 29 Nov. 🌐 To get high faster and cheaper he started injecting this straight into his veins, a dangerous method known as ‘mainlining’.
[UK]Guardian Guide 22–28 May 7: As Lenny Bruce once said of mainlining smack [it is] ‘like kissing God’.
[UK]N. Griffiths Grits 344: A coulduv mainlined inner bogs burrav lost me fuckin spike an am fucked if am gunner use anyone else’s.
[UK]K. Richards Life 260: I’ve never mainlined.
[US]C. Stella Rough Riders 54: The fresh needle marks were probably the first two times Nathan Barron had ever mainlined a drug.

2. to inject intravenously in non-drug use; also fig.

[US] in T.I. Rubin Sweet Daddy 30: Here I am mainlining this ammo junk – ammonophiline [i.e. an asthma treatment].
[Aus]Adamson & Hanford Zimmer’s Essay 104: Watch the speedo. / Plant your foot until the big V8 starts to mainline juice.
[UK]K. Lette Mad Cows 67: Half-masting the white flag of surrender she’d been running up to fate, Maddy main-lined that Malteser.
[US]J. Ellroy ‘Hot-Prowl Rape-O’ in Destination: Morgue! (2004) 270: I mainlined some mocha.

3. in fig. use.

[US]T. Fontana ‘Straight Life’ Oz ser. 1 ep. 5 [TV script] Drugs ain’t the only thing to get addicted to. Some people mainline their work. Some people snort ESPN.
[Aus]L. Redhead Cherry Pie [ebook] [I] drank two cups of coffee (no need to mainline the entire plunger when you weren’t hungover).
[Aus]T. Spicer Good Girl Stripped Bare 274: I decide to mainline this shit [i.e. the onset of the menopause]. And talk about it all the time.
[US]J. Ellroy Widespread Panic 189: The martinis materialized. Phyllis mainlined half of hers.