The "driving pleasure" you get from being behind the wheel, while also receiving head. Upon ejaculation, you must slam your car into any vehicle next to you.
Farfanoogin is the way a moron pronounces Fahrvergnügen, a German neologism meaning "driving enjoyment." It is often parodied or used when the speaker does not speak German, but wants to use a German word.
Moron: "Did you see that German guy? He's a real farfanoogin if you no what I mean."
Normal person: "I don't even know who you are. Why are you in my house?"