From Thomas Dolby's blog (N.B. his real last name is Robertson as referred to in the post):
At my previous school in London I was good friends with Shane MacGowan, of The Pogues. He and I used to sit together in the back row of English Lit. He was extremely smart. On one occasion during a boring reading of some classic novel or other, the teacher spotted me and Shane nattering. He singled me out saying something like ‘what figure of speech is “indubitably”…. Robertson?’ Shane whispered under his breath: ‘It’s an onanism.’ Ha. ‘IT’S AN ONANISM, SIR!’ I blurted out. Deadly pause. ‘Robertson, please come up to the front of the class, take down the Oxford English Dictionary and read out to the class the definition of the word onanism.’ Which I did. Much to the delight of Shane and the rest of the class.
There's a much longer entry about long-ago Shane here.
Know your OED, kids, it will save you from embarrassing moments in front of the class while your smarter more well-read friend cracks up in the back.
Edit: for typo, and weird symbols appearing instead of quotation marks but now they've gone again. Hmmm.