The foaming that occurs in the back of your mouth while talking at full-on motormouth speed. Usually causes discomfort and interrupts rambling conversations.
Sarah: "...and then I was like, OMG that purse had Brianna's cell phone in it and I could totally hijack that and then--"
Mike: "And then..what??"
Sarah: "*gulp*Yeah sorry, I got conversation rabies for a moment there. So anyways..."