Kinda like when an amputee can feel a limb that is not there. It is when you can feel your penis in one spot when it is actually in a different spot.
You know when you tuck your penis and balls back and cross your legs to look like a girl.. Well in this case tuck the penis to the left and back but leave the balls to the right in front, don't push the balls back. Now move around slightly and like MAGIC your phantom penis feels like it is where it belongs centered over your balls in the middle even though it is not. Cool huh!