Sticky Bonus

A sticky bonus (also called a non-cashable or phantom bonus) is one where the bonus amount is removed from your balance when you request a withdrawal. You can play with it and keep any winnings above the bonus amount, but the bonus itself never becomes real money.

Here's an example. You deposit $100, get a $100 sticky bonus, and your balance shows $200. You play through the wagering, and your balance reaches $350. When you withdraw, the casino strips off the $100 bonus and you get $250. The bonus served as extra playing money, not extra cash.

Sticky bonuses aren't always bad. Because the bonus money is "free" in the sense that you were never going to keep it anyway, the wagering requirements are sometimes lower. What matters is the overall value: how much will you statistically lose from the wagering compared to how much you're gaining from the extra playing time? If the wagering is low enough, the deal can still be worth taking.