An epic burn. Practice so it will roll right offthe tongue and and use when people are drinking so that there will be maximum nasal spewage for effect.
When someone is utterly bullshitting their way out of something, commonly the failure to attend an event or to give someone something (i.e. gift, debt, etc.)
Bob: Bro, sorry I missed the party, but my girl was all on me last night!
Mike: Dude, your girl was AT the party last night. I can see the shit dribblingout of your mouth, dude.