You might hear a player say “No hair” if they are talking about their “Top” or “low hand” that is set. To have “No hair” means that you have nothing on top. No strong cards in the two cards that have been set as your low hand. An example of “No hair” would be if you had a 9 – 5 set as your top. If you had a pair of kings, then there would be no reason to refer to your top as having “no hair.”
You might also hear players chanting “No hair” before the dealer turns over her cards to reveal her hand. This would mean that the player has a low top hand, and is hoping the dealer has an even lesser hand.