Etiquette for joining other riders?

So I was riding home from work the other day on the freeway, when I happened upon another rider. We waved as he passed me and, due to traffic, I ended up changing into his lane. My route had me following him for a few miles, during which I rode a few bike-lengths back, on the opposite side of the lane from him. I noticed though that he kept looking over his shoulder at me, and I couldn't help but feel like I was doing something wrong.​So I guess, what does etiquette dictate you do when you happen upon a random rider? via /r/motorcycles https://www.reddit.com/r/motorcycles/comments/cgp1s0/etiquette_for_joining_other_riders/?utm_source=ifttt