Green’s Dictionary of Slang

throw (it) into v.

1. to tease.

[US]Ade Artie (1963) 43: Throw it into him hard. Call him ‘foolish Wilson boy.’.
[US]C.L. Cullen Tales of the Ex-Tanks 48: His pals threw it into him about being a chaw-bacon and a would-be welcher and he subsided.

2. (US, also chuck into, shoot into) to impose upon.

[US]C.L. Cullen Tales of the Ex-Tanks 30: The collector, because I was a bit shaky after my little month of it, thought he could throw it into me. [Ibid.] 169: ‘I’ve just chucked it into him,’ said the Memphis trainer [...] ‘by claiming this [puppy] for fifty. I’ll make ten times that out of her.’ [Ibid.] 313: I [...] shot one into the manager about being delegated by the City Hall employees.
[US]D. Runyon ‘The Defence of Strikerville’ in From First To Last (1954) 21: They thought the top was throwing it into our gang for double duty.
[US]D. Maurer Big Con 15: The mark was taken on the strength of the ‘con’ which the roper ‘threw into him.’.

3. (US tramp) to talk in slang.

[US] ‘Jargon of the Und.’ in DN V 465: throw it into one, To talk to one in argot.

4. to assault, to kill.

[US]J. Thompson Savage Night (1991) 109: If he thought I couldn’t do any better than this, get it thrown into me by the guy I was supposed to throw it into.

5. (US gay) to sodomize.

[US]Maledicta III:2 233: Still more words of this fucking vocabulary are [...] throw it into someone.

6. to have sexual intercourse.

[Ire]P. Howard Miseducation of Ross O’Carroll-Kelly (2004) 139: I’m about to ask her [...] which one Robbie Williams is throwing it into.