Chain tattoos are something normally associated with newer riders. You don't need chainguards or special lubes, you just have to keep your leg away from the chain. I think it's something you'll have to figure out for yourself. I recall getting tattooed when I was starting, but over time the frequency became less until now I can't recall the last time it happened. Unfortunately, I can't articulate what I do to avoid it. Much like walking, it's something that happens subconsciously.

I suspect all you need to do is to pay attention for a while and make sure you keep the bike away from your leg. After a while it will become second nature much like unclipping before you stop.