What is Get The Fuck On?
1. A slang term conveying disbelief in what someone else says or does.
2. A slang term telling someone to shut the fuck up and drop whatever they're saying or doing because it is pissing you off.
The meaning is largely denoted by listening to the persons vocal inflections who is saying it.
1. Tom: Man, you shoulda seen this chick..she looked just like Rhianna, she was so hot. And she was all over me!
Greg: Man, get the fuck on! Ain't no bitch lookin like Rhianna gonna wan't shit to do with your ass!
2. Tom: Is that your girlfriend, Amy? Man she's hot as hell. I'd tap that ass in a second.
Greg: Man, you need to get the fuck on with that shit. Lemme see you fuckin' wit my girl and imma break my foot off in your ass!