Is there any possibility to lower the withdrawal fees?? Now we have to spend around 6 dollars for withdrawals.

As mentioned above try an internal exchange service and convert BTC to LTC for cheaper withdrawals. Use cryptogamblershub for transferring BTC to Dinabot and withdraw the received altcoin in few minutes.
Internal exchange service isn't available with Stake. Earlier we've got this access where it is possible to any cryptocurrency for specific fee, and that has been taken away for some reason. Now the best choice is to try your luck for a $6 roll and if lucky you cover the fee with the winning or else you need to think the transaction fee has costed you $12.

Oh my bad, you are right only third-party services are available for exchanging the funds on Stake or Primedice. Your last suggestion makes sense to cover the withdrawal fees but I am that person who busted $300 for getting $5 back on limbo 2x multi

Better to pay the fee than risk
