User blog comment:TheTobarMethod/Guide To ADC/@comment-4012115-20130223165328

You should art "Trading" (or however you call it )

means:

If you don´t last hit a creep you try to hit a enemy if he try to get a last hit

=

The enemy will get the creep but take damage (can`t fight back)

or

The enemy will not get the creep and fight back (he does damage to you but will lose gold)