what should a man do to increase his sperm production, i asked this because i use to ejaculate less sperms whe?

hi there i am no expert in this feild but after researching alot me and my husband discovered a herbal supplement called speman,since taking this product my hubbys overall amount of sperm has increased to almost double the amount also he feels that when he cums it comes out alot faster than it did before[sorry for tmi],before it seemed sluggish and slower and not much there but theres definatley an improvement hope this helped if you are intrested in using this product i sugest you do your own research on it and decide from there this item is sold on ebay good luck,x