Meaning of Discharge

My normal discharge when not on my period is minor white/clear mucus, but I randomly discharge a water substance.. It doesn't happen every cycle and only lasts for a few days, nor does it have a specific time in my cycle. Absolutely everything else is normal so I really have no clue. I was just wondering what it meant, like if I'm extra fertile for those few days or what. Just thought it might be helpful information in the future..