Spoken lyrically and with an emphasis on the 2nd 'now' i.e Dow-now-noooooowwwwwwww, this is used when someone is being a stupid fucking nob head. The person it is directed at is unaware that you are using an alternative method of implicating that they are, in fact, a complete fucking tool of the highest order.
1. Two collegues, who are familiar with terminology, are in a meeting with co-workers. One of the co-workers is speaking and is talking shit. Enter...
2. John "I'm the best at snurgling rumpter boxes"
Richard "Dow now now"