I've never heard of it before, but I found the quote below via google, from page 12 of the PDF at the link below:
Hang gliders are tailless aircraft and have been developed since the 1950’s. They are not prone to the fast oscillation known as ‘pecking’. Pecking is a rapid oscillatory motion around the pitch axis of the aircraft.
The term is used elsewhere in the same document, use the find function to locate other examples.
https://repository.up.ac.za/bitstrea...hapters1-3.pdf