| Re: Question about "Jacks Or Better"
It's not really a bluff, it's just another betting round. After the openers, anyone can bet. If you fold, and no one has trips or better to win, you're out for the rest of the game. If you call and no one qualifies, then all hands are dead, and you re-deal.
Short answer= yes, you can bet even if you don't have it. It's part of the game. | 
