I'm a customer of betonline (tigergaming) and don't want to use coinbase, even through an intermediary wallet, because they can and will trace the account, so where can I sell my btc?
If you want it to be completely untraceable or anon, I hate to break it to you but you won't have much luck. You could always sell the BTC through localbitcoins with cash or whatever but that's my best advice I'm afraid.
Did you win a lot? If you don't mind me asking.