It's a very sweet saying for something that one thinks is absolutely amazing and has no other words for.
2. AwesomeSauce is used once a greeting has occured.
Other Guy: Yeah, it was AwesomeSauce
2. Guy One: Hey
Guy Two: Hey
Guy One: You okay?
Guy Two: Yupp, you?
Guy One: Yeah
Guy Two: AwesomeSauce