Euphemistically used to replace wanking or a hand job. Imagine holding a cup of Nescafé in your hand. If your imagination can't stretch to Nescafé, Aldi value granules will suffice. Then imagine shaking someone's hand with it. Then see what you've just done in reality. You see.
The whore gave Hugh the old Nescafé Handshake before selling her story to the classy upmarket newspaper 'The Sun'.