The act of simultaneously pooping and ejactulating. Term comes from the combination of the wordsjizz and feces. This usually happens when something is so exciting and/or arousing that it causes one to not only ejaculate, but also shit oneself. Fizzing can often be accompanied by loud outbursts, moaning, and hurried trips to the bathroom.
Jon: "Wow, did you seeRonaldo's goal last night?"
Bob: "Yeah, it was awesome. I saw it on Sportscenter and started fizzing."
(phrasal verb) When you're "fritzing out" you're losing your grip on objective reality and paranoia is kicking in. You think others are plotting against you and so you take decisive action them thereby increasing the likelihood that people really are plotting to get rid of you because you're insane.
Trump is totally fritzing out. He thinks that the people closest to him are secretly plotting against him. That's why he fired James Comey and Sean Spicer and is tweeting against Jeff Sessions.