After a sentence, either sarcastic or
serious when people have started laughing, use 'No seriously' to either show
A) You're serious and want them to stop laughing because it's
not funny
or
B) You're
taking the piss out of them by not being serious
Example:
Amy "Hey Ashlee, do you want to come with me and my extended family to
woop woop for a month or two? It'll be super fun!"
Ashlee (laughs) "Yeah, a month or two in woop woop with your extended family will be super fun!"
Amy (pissed off) "No, seriously. I think I'll go ask Sarah. (under her breath) Bitch."
Jim "Dude, last night I had a totally
rippin' threesome with
Carmen Electra and Jessica Simpson!"
Joe (laughs) "Like fuck you did"
Jim (laughs) "No, seriously. I jacked off alone to Judge Judy."
Joe (disgusted) "Oh, dude" (leaves)