However, if you hold your three notrump bid, partner is not allowed to correct. If your partner is forgetful, you want to use the stop card when your bid is preemptive and not use it when your bid is strong. If your partner is reliable, use the stop card only on bad preempts. The more cards you display, the stronger your message. Six Pass cards shows a Yarborough.
Some players prefer to indicate emphasis by the way they put their bidding card on the table.
Slamming means this is the final decision for the partnership. Floating a bidding card indicates resignation. Bidding boxes are a wonderful thing. You do not need to pay attention all the time because you can review without asking for a review. You do not need to worry that other tables will hear your auction.