It happens a lot in golf. You make some almost perfect swings until you've got the ball in front of you and you have to hit it. If you went on doing exactly the same, the ball would fly straight and get to where it's supposed to with no trouble at all. But when you see the ball in front of you, something snaps inside you and makes you screw up. Inexplicable, magic and vexing as hell. This is called last cast syndrome or lastcastitis.
You need a partner for this game. The good thing, however, is that your assistant doesn't have to be a fly-caster, just know what to do.
Objective of the game
To acknowledge and try to correct the defect of altering your technique, destabilizing the system and usually adding more force and/or lowering the rod too much in the last cast before laying it down.
A partner that knows exactly what to do and when.
Vary the length of line in the air every so many times you do this. Start making false casts. Suddenly your partner calls out, "Now!" That's the lay-down forward cast.
Timing the call is the key to this exercise: just before the forward stop. Your partner has to give you a little time for you to know that you have to lay it down, but not enough for you to alter your technique on that last cast.
Sometimes he (or she) will make the call after only a couple of false casts. Other times, she'll wait longer. But the call must always be unexpected.
Lay the line down in back of you following the same instructions except the call, which must be just before the stop of your backcast.