After a call has been made that stops play and the offensive player has the disc in their hand, the defensive player checks to make sure that both the offense and the defense are ready to play. The offensive player then presents the disc to be "checked in." The normal procedure has the offensive player holding the disc at about waist level with both hands insignia side up. The defensive player touches the disc and announces "disc in." Play can not restart without this occurring. In practice, the offensive player may sometimes NOT want the disc to be checked in, either because they disagree with the call and the "conversation" about the call has not been completed according to them, or because they have something to tell their team. In those instances, they may hold the disc behind them and NOT allow the defensive player to check the disc in. Is this inappropriate behaviour? Well, that's a difficult one. If the offensive player is using it to gain an advantage by communicating with their team, it is inappropriate behaviour, but there's not much that the defensive player can do about it(perhaps call a delay of game?). In the second case, it may or may not be inappropriate behaviour. Sometimes disputes about rules are not reconciled despite one party's insistence that they are. Because tempers may be flaring during the argument, withholding the disc from check sometimes only makes things worse.