what's funny here it's indeed truth
human semen has part of zinc in it, zinc deficiency from relentless masturbation will give watery semen; also magnesium plays a good part in semen quality
that's why many bodybuilders take magnesium and zinc supplements to boost their semen quality;
vitamin c (or any citrus fruit in general) will also 'lace' the semen with its fruity aroma and taste, another reason people say to eat pineapple for these "purposes"
vitamin b-12 = folic acid is also helpful
if you want to go further, amino acids like levocarnitine, levoarginine and so will also immensely boost semen productions (some of vital amino acids which are only found in nonvegetarian food)
^all of these supplements are easily available in market, go try it along with semen retention and see the improvement
also, try ashwagandha, will help a lot (but reminder ashwagandha is not suitable for everyone, it is also mildly hepatotoxic = will harm liver function with bigger dosages and from longer use so use it in accordance to your 'tolerance')