Duelbits has a tipping feature on the site. It's available through the chat window. You have to click on the name of the user you want to tip. You will then see a new popup on your screen with some stats about that player and underneath the username is a Tip User button. Click on it, enter how much you want to send, and finalize your transaction.
Do you know how many casinos and gambling websites have something like this TIP function, and can we send any amount of coins we want, or it's only fixed numbers.
This could be interesting addition for this Withdrawal Table but I think it would take a lot of time to investigate and test so many websites.
Gambling websites that I use every day don't have tip option, or I could not found it.