Comes from the name of the Channel Nine News Reader in South Australia Kelly Nester, and is rhyming slang with "molest her" or "molest 'er".
You are with a friend on the street and you see a hot lady walk past. You say to your friend "Check her out - I'd give her the old Kelly Nester". To which he'd reply "Kelly Nester?" And you'd say "Yeah - Kelly Nester - love to molest her."
by Sean Springs November 10, 2009