Eric Andre always sits to the guest’s left, while Hannibal stands to their right. They made this choice deliberately so that the guest can never have both of them within their eyesight at the same time. The guest would be talking to Eric, then suddenly Hannibal would do something crazy and usually loud, prompting the guest to turn to him, giving Eric time to grab a prop to do his weird antic, and so on and so forth.
All of this serves to envelop the guest in complete chaos.