How long of a wait do i have to experience until i can be sexually active again. after donating 825ml of plasma.

No limit: For plasma donation, they take out blood, spin out the plasma, and give you back the red blood cells. There should be no limitation to physical activity, except you should definitely rehydrate and eat healthy foods to replenish your plasma optimally.

As little as you can: No time like the present as long as you have a willing partner whose willing and able. As they say, go for it!