Seemingly the frug was a dance in the 1960s, but frugging appears to have 2 meanings nowadays:-
In market research, frugging is "fund-raising under the guise of research". For example, when someone purports to be a market researcher conducting a statistical survey, when in reality the "researcher" is attempting to sell you something.@Zom
- On a more criminal note, it is a mix of "friendly" and "mugging". It occurs when someone (or a group of people) pretends to be really friendly, and hugs you, but when they are gone you realise your watch, jewellery and wallet are missing.