What is a class way to conduct the lag? Do you count to 3 or just wait till your opponent shoots?
It's iffy, as long as you don't wait too long till after the guy shoots you can do it whatever way. As long as the second guy's ball has not hit the first rail, you can shoot any time before then.
After it hits the rail I'd think that he was waiting to see how hard the shot was and was trying to use that to calculate how to his his. That case I'd call for a new lag.
Also the balls can't hit, nor can they scratch or hit the side rails. Anyone that hits the side rails or scratches, or crosses over to the other side of the table loses the lag automatically.
It's also against the rules to do a practice lag right before the real lag. If you're warming up, go ahead and hit a few lag shots to get the speed of the table down, when you are ready to start the match, there is no "practice lag".