Back when computer monitors were big enough, my cat would sit on that and I would have to keep moving his tail out of the way

I've been consistently moving him onto the floor or my lap if he steps onto my desk size mouse pad while I'm at my desktop. Eventually he picked up on the fact that he's not allowed on the mouse pad, and will now either sit at the edge of it, or climb into my lap.

There's also a catbed behind my second monitor, which he preferred for a long time, but my lap has been the more popular option in recent months.