i just do it the natural way by drinking ample fluids and eat multiple servings of fruits a day.
i have been wanking since i was 12 so maybe my body naturally produces more than normal amount of semen to replace any i loss because if i do not ejaculate for more than 3 days, i will feel rather uncomfortable and if i have an erection during this time, its also very full and hard.
i try not to have too long gaps between ejaculations because of more than a couple of days, post orgasm, i will have a lot of surplus semen still inside the urethra and i have to go urinate to clear everything not shot out which results in very bubbly pee rofl.