"Dobbing involves presenting a single hookbait in areas of the swim where you expect fish to be. In extreme cold weather feeding bait can put them off, but dobbing a single bait can be just enough to tempt them!"
It works in freezing weather for sure.
It's a way of searching all over the peg without feeding any bait.
On them freezing days and when the water is gin clear etc.
Works well on snake lake kinda venues if you can reach some far bank reeds.
A large piece of punched Bread can work, as can maggot(s), off the bottom or on the deck.
The carp can be quite lethargic in the cold weather, if you start catching there can sometimes be a "ball" of them in your peg.
I tend to use a 4x14 float with all the weight except 3 number 10's under the float so that the bait has a slow fall through the water, keep lifting and dropping in any like area as strange as it seems fish can be away from cover so dont just do it near any cover try the bare bank as well
I have never thought of it as "dobbing" but I did learn that a single red maggot, half depth and with no feed can be deadly in Winter in the near margins from a very good angler who has won big events. He shared the information after I saw him, on another lake, win a match using the tactic. I was puzzled as to how he was catching from the margins midwinter. He in turn had learned it from another angler who had won a match with the method the week before.
Far bank dobbing would involve the use of a pole longer than 10m. And as @notneeded will tell you, thats a place I don't go to.
A single white maggot 6 inches off bottom about 5m away from where l had been trickling maggots for a couple of hours resulted in an F1 almost immediately. Fishing a match at Cefn Mably one very very cold winters day, after the silvers but hadn't had a touch. Decided to shallow up slightly and ping 2 or 3 maggots on a different line. Didn't get to the pinging bit though and caught F1 steadily till the all in. Opened my eyes to dobbing.