This one comes from the Daily Caller. It is a mashup of “foaming at the mouth” (extremely angry) and “groveling in (something)” (to interact with someone in an overtly agreeable manner). So did the writer mean that the Party was angry or overtly agreeable? My guess it was the former. As an aside, this is also another example of using the word “literally” incorrectly. If it’s literal, then it happens. A big thanks to Ralph Aikman for spotting this one.