This is where they come from:
link 1

[S: For what? W: "A MILLION HOUSEHOLD USES!" S: Such as? W: Uhmm...Tying up very small parcels, attatching notes to pigeons' legs, uh, destroying household pests... S: Destroying household pests?! How? W: Well, if they're bigger than a mouse, you can strangle them with it, and if they're smaller than, you flog them to death with it! S: Well *surely*!.... W: "DESTROY NINETY-NINE PERCENT OF KNOWN HOUSEHOLD PESTS WITH PRE-SLICED, RUSTPROOF, EASY-TO-HANDLE, LOW CALORIE SIMPSON'S INDIVIDUAL EMPEROR STRINGETTES, FREE FROM ARTIFICIAL COLORING, AS USED IN HOSPITALS!" and so on and so on ]

English---stringettes, all about Monty Python:
link 2

French---stringettes - Google pages are mostly about an undergarment called 'string'. Maybe it's them who have taken the English word 'string'and added the -ettes.(not related to Monty Python) The French dictionary Trésor does not have the word however. It would be in the French Urban dictionary if there were one.

When you google 'stringette' ,you get entries about horse races
and horses
link 3

oef! This is the whole lecturette.