To help fap with your fanny. The name was invented by Auntie Mabel on the BBC TV Programme 'Come Outside'.
Auntie Mabel: "Jizz in the bag, jizz on the wrapper. Jizzkerchiefs!"
Jizzkerchiefs are handkerchiefs, tissues, cloths or anything else with liquid absorption capabilities, used for the wiping up of jizz off the floor, or any other surface onto which it has been shot.
ME: Oh shit! Sorry mate, I jizzed all over your floor!
FRIEND: DAMN YOU DANIEL! Now where did I put the jizzkerchiefs?!!
**a short while later**
FRIEND: Right, here's a couple of jizzkerchiefs, now you get this floor cleaned PRONTO! Count yerself lucky I'm not charging a cleanup bill!