What Is the Risk of Being Long Gamma and Long Theta?

It is impossible to be long Gamma and long Theta simultaneously with a standard single option position. Long options are always long Gamma (benefiting from price movement) but short Theta (losing value daily).

If a complex strategy is structured to be net long Gamma and net long Theta, the risk would be that the positive Theta is often offset by a negative Vega, meaning a drop in implied volatility could cause a loss.