If you think he did it on purpose, go ahead and call it intentional. What I normally see is poorly coached players "boxing out" instead of jumping and undercutting the rebounder behind him. I had one this season, and the defender's response was an incredulous, "but I was on the inside."

Me: "You still can't push him or undercut him."

Maybe This Will Help ...
 

Ball-Handler / Hand-Checking
Any illegal use of hands, arms or body, offense or defense, that slows, prevents, impedes the progress, or
displaces an opposing player, due to the contact, is a foul and must be called. When a player places both
hands on a ball-handler, it is a foul. When a player continuously places a hand on the ball handler, it is a foul.
When a player continuously jabs a hand or forearm on a ball-handler, it is a foul. When a player jabs a hand,
or forearm, on an opponent to control his or her movement or gain an advantage, it is a foul. If the dribbler’s
rhythm, speed, balance, or quickness are affected, we should have a hand-checking foul. Tactics using the
hands, arms or body that permit any player, offense or defense, to control (hold, impede, push, divert, slow
or prevent) the movement of an opposing player is a foul.

Post Play
As lead, let’s find the post matchup as soon as possible so that we get the first foul. When a player uses hands,
forearms, or elbows to prevent an opponent from maintaining a legal position, it is a foul. When a player
dislodges an opponent from an established position by pushing or backing in, it is a foul. Let’s not allow a
defender to use a leg or knee to move a player off the block. When the defense undercuts, initiates lower
body non-vertical contact, slaps, pushes, holds, elbows, forearms or just generally demonstrates rough,
physical movements or tactics, this is a foul on the defense. Let’s make sure the offensive player isn’t holding
off the defender, or holding him with his off-hand. When the offensive player then uses the swim stroke,
pushes, pins, elbows, forearms, holds, clears with the body, or just generally demonstrates rough physical
movements or tactics, this is a foul on the offensive player. Don’t let players redirect, impede, displace, or
dislodge.

Pure gold...even thought the words "butt", "crouch" and "tummy" are not used.

Rule Four - Butt ...
 

Hey, I can add them if you want. Or, even better, copy, and paste, the two paragraphs, and edit it yourself, adding as many butts, crouches, and tummies as you want. Go ahead. Knock yourself out.

Don't be a crouch snuffer.

Officiating.com : Basketball : Undercut Foul — Intentional and/or flagrant

After reading this article and then experiencing one in a game it has me thinking we need to consider IF sometimes. Any thoughts?

yes. I think you asked about it in post 28, and got some good answers and follow-up questions that you failed to address.

First, the correct term is not "butt", but "tuchus", :p. I am sorry, as a Moderator I should be held to a higher standard, but (:D) I could not help myself.

Second, any time a player uses his tuchus make contact to gain advantage in violation of the rules, that should be called a foul.

MTD, Sr.

Bob do you have a link so I understand better what I failed to address?

My crouch hertz.

Here's the question he is talking about:

Posts 30 and 31.