Beard on tash with a little bit of mash

I assume derived from "chinny chin chin". To point out something said is a lie. A version of the saying for teenagers.

"Beard on tash with a little bit of mash" implies the lie is ludicrous. If less ludicrous you can use "Beard", "Beard on" or "Beard on tash".

All sayings must include a chin stroke.

Believe this comes from Portsmouth (Pompey) and surrounding areas of the South of UK.