This is a spoof McDonalds advert, I take it?

"Dogging it" is American English, informal, and means to act lazily, or to not do your best.

It is a "slang" expression so the definition / meaning is going to be imprecise. However, as I understand it, it is rather similar to saying that someone is "slumming it". That means that someone is just plodding along, and not putting very much effort into what they are doing. For example, it would be like a college student doing everything indifferently, with about a HALF-EFFORT. Another optional meaning would be to convey that "dogging it" is doing something, but doing it poorly. For example, an athlete performing, but poorly and with mistakes. Perhaps someone else knows of a more precise meaning, but this is my understanding. Remember; slang is simply a terminology that someone "makes up". It means, whatever the originator intends for it to mean. How can we really know who the originator of slang is, and what it means? .