get off on a sidetrack

1. To begin discussing or addressing a topic not relevant to the main discussion. I tried to address the customer's problem, but she kept getting off on a sidetrack, and I couldn't understand what her actual complaint was. In the middle of our conversation about my finances, my advisor got off on a sidetrack about current events. All of a sudden, in the middle of dinner, Tom got off on a sidetrack about his time in Peru.

2. To cause one to begin discussing or addressing a topic not relevant to the main discussion. In this usage, a noun or pronoun is used between "get" and "off." I know you're interested in my time traveling through Russia, but if you don't stop getting me off on a sidetrack, we'll never finish this lesson! Her flippant remark sparked an intense argument that got the whole class off on a sidetrack. The kids need to finish their homework, so please do not get them off on a sidetrack.