Positive punishment is giving in to him. You are giving him exactly the attention he is seeking. Basenji do not like being ignored or shut out. That IS a form of punishment to them !
Agree, they don't like to be ignored. That comes under the heading of negative punishment. But there are things they like less. Depending on the dog, the skill of the trainer, and the punishment meted out, positive punishment can be extremely effective, but timing and choice of consequences is critical, so it's not something I recommend. Punishment is a loaded word, but it is the word used in operant conditioning. It evokes some terrible, painful consequence, but might be something as mild as a well aimed water pistol, which for some Basenjis (and some cats) would be reason enough not to repeat the action that caused it.....while with others it could turn into a game of trying to nail the feet and escape the spray. Without knowing the dog it's hard to guess what the result would be, which is why I am not suggesting it.
The very best form of positive punishment is self inflicted, e.g. electric fence for livestock, invisible fence for dogs (if they don't learn to run through it), because of the consistency which a human trainer may lack. The consequences for most are unpleasant enough that they don't care to repeat the action that causes them. Horses seldom challenge electric fence if it's working properly, although some seem to detect when it is turned off!