Defending the post, always have a strong base, don't get displaced, be low in a stance, have a hand around to discourage a pass (they have a no-catch zone), instead of catching the ball on a straight line between the ball and the basket, he's off line at little bit, which creates a tougher shot.
Don't give any angles on a catch, don't go for a phantom steal, relocate dead behind as the pass is in the air, down in a stance, about one foot away (not body to body), "short-arm" distance, close enough to touch him with your short arm (forearm). Stay away from using the baseline hand as the short arm, it's too easy to spin off, put your inside hand on him, the other hand is above your shoulder, contest with the hand that's already up (it's a lot quicker), don't try to block a shot, it's hand to face (then hand to nose if he makes 4 or 5 shots). Make sure your feet are able to move, not surrender defence where he goes right around.
Wall up on a shot, as he turns and gets ready to shoot, get your hands up and behind your ears (if you get hit, your hands will come forward to vertical), maul him with your thighs, make sure he shoots over you, don't give any angles.
Turn, hit and go get, put your butt through his spine on the first shot, the first box-out sets the tone.