Cockney rhyming slang - Jacob's Cream Crackers (a brand of crackers) = knackers
Meanings
(UK, plural, plural-only, slang) Testicles.
He has also provided some of the show's funniest moments - when enjoying a bath with Three Degrees star Sheila Ferguson he told her: 'I'm comfortable with anything, love, but you don't want to see my 'Jacobs' hanging out.' 2004 December 8, Sherna Noah, “Joe's jungle 'experience'”, in The Birmingham Post:
I used to have a Velo seat, which is pretty similar to the KH in design, and I got rid of it for the same reason. The padding was so deep and spongey that my Jacobs used to float to the top as I rode along. 2005 July 2, Mikefule [username], “Re: Nut buster seat”, in rec.sport.unicycling (Usenet):
Horseshit every match matters and Alex Ferguson would drag his players out of the club by their Jacobs if they made such a statement. 2008 November 25, Baldoni, “Re: Amazing...”, in alt.sports.soccer.manchester.united (Usenet):