The phrase "to ramble on" means to talk or write at length without focusing on a particular topic, often going off in different directions and not staying on point. Full definition
A few of Revengeance's cutscenes ramble on for too long, but the jaw - dropping absurdity of those non-playable moments more than makes up for taking control away from players. (polygon.com)
DO go into your bosss office with a simple acknowledgment that you and your coworker are dating, but DO NT ramble on about the details of your love life for five minutes, says Olen. (petesgrillandpizza.com)