A sticky bonus is a casino bonus you can wager with but never withdraw. When you cash out, the original bonus amount is subtracted from your balance — only the winnings generated on top of it are paid. Compare with non-sticky bonuses, which separate bonus and real-money balances.
Also known as: phantom bonus, non-cashable bonus
Sticky bonuses inflate your effective bankroll without inflating your potential withdrawal. A $200 deposit + $200 sticky lets you wager $400, but if you hit $600 you withdraw $400 (the $200 sticky stays with the house).
Non-sticky bonuses are mathematically friendlier: you play with real money first, and the bonus only activates if you bust the deposit. They are rarer because they’re costlier for the operator.
Read promo T&Cs to identify which type you’re getting. Words like "non-cashable", "phantom", or "sticky" in the terms are the giveaway.