Penalty?

[DJ_NV]

NCAA: 7-1-5-a-4.

NF: Check in rule 9 for noncontact fouls by players and looks for the words "disconcerting words or acts". (I don't have my rulebook with me.)

Now, having said that, in my opinion be very careful about calling this foul. I believe that a lot of latitude must be given to the defense because the offense knows the snap count and just as the offense tries to get the defense to jump with hard counts, etc., part of being a defensive lineman is to anticipate the snap and that includes flinching, etc and it's up to the offense to not move.
Now with that in mind, if you can clearly tell that the DT or NG is clearly ignoring the ball and even the play that's about to go and is clearly just being an *** to the OL in front of him, then I think a stern warning after the play is in order. Some guys don't agree with me as they feel that the onus is completely on the offense, but just as some acts are illegal because it's not part of the game, i.e. "Where's the tee?" etc., I believe that excessively chucking and flinching on almost every play is outside the spirit of the rules and the intent of the game and is borderline unsportsmanlike. As a former defensive lineman myself, I feel that they need to be a man about it and come off the ball hard and beat their opponent at the LOS, not jerk around with this "chickens***" behavior. If it's strategy and they can make their opponent possibly false start at a critical time and they don't overtly use confusing or 'disconcerting' words, then good for them for backing Team A up 5 yards, but I've had D linemen in JV games do it play after play and it gets old. I don't think I've ever flagged it more than once--and that was after repeated warnings to knock it off--usually a decent amount of preventive officiating gets the job done, but just know that in extreme cases you have a rule to back you up. Again, some guys don't agree so you'll have to go by what your association and your crew chief says, and you'll eventually figure out how you want to call it.

Just my .02