The act of doing something completely awesome. It can be used to explain how something is being done.
John: Did you see how many points Keith got on Fantasy Baseball?
Mitch: Yeah, he is doing jesusly
The act of being a complete moron. It replaces more offensive words that piss people off.
Person 1: Did you see that guy use his baby as a hacky sack?
Person 2: Yeah, what a tard-wad.