The safetiest that i know is to use the faucet bonus don't spend your bitcoin from your wallet just use the faucet bonus and make some profit if you are not lucky to get large amount.. its better to stop so that you can control your self for being greed..
safe way to gamble is just play with the amount of money you can afford. If you go to the supermarket and normally you buy a donut. Do not buy the donut and gamble with that money.
can't gamble without any real money. There is no such thing as playing safe with risk but you can always stay away from it if you don't want the risk of loosing.