I was having a hard time getting this by actually doing the CB part, so I looked up alternatives, and I found that the achievement doesn't require YOU actually win the presses, just someone on your team. If the computer wins the presses while you control a lineman, it will still count when the same player reaches three successful presses.
So I did this during my Full Set grind. Use two controllers and play two minute quarters with no accelerated play clock. Have your second controller get the ball and when choosing the play, choose Concept --> Deep Pass --> Verticals --> Four Verticals
. Any version would work, but I used the one where the RB runs through the line and goes left.
On your main controller, on defense, choose Concept --> Cover 1 --> Cover 1 Robber Press
. Then, before you snap, hit and do
which will choose a coverage adjustment of 'Press'. This will move your CB's closer to the line and encourage your CB's to press their WR. Then, just hike the ball with your second controller while you control one of the defensive linemen or linebackers.
Now with your second controller, you want to throw the ball to
when he gets reasonably open, about 4-6 seconds into the play. When he gets tackled, mash
to do a No Huddle which will keep both the plays the same and rush everyone back to the line. You need to repeat the coverage adjustment to encourage press, but then you can repeat the snap. Keep repeating this through the first quarter and the second quarter if necessary. Eventually, Lockdown Corner should unlock as your CBs will reach their third press win. This method worked much faster for me than trying to win the press myself, and I was able to obtain the achievement in the first quarter of the first game I played. I wasn't using any special rosters, or even the best team available when I got the achievement.