Define I'd Do Him Meaning

I'd Do Him
An emphatic or yielding response to a question regarding what one thinks of a dude when asked by a girlfriend.

Her: "Dude in the blue plaid, yay or nay?"
She: "I'd do him."
Her: "Of course you would, but not what I asked."
She: "Ugh, fine. What to join us?"
By Marika