A cpl of Q’s - 1st, I assume this is NOT urine, right? Does it have any smell? If it’s a clear, kind of slippery liquid, that sounds like so-called ‘pre-cum’ or pre-ejaculatory fluid.
Next Q: How old are you & what’s the frequency of any sexual activity, either masturbation or sexual activity with another person? If you are not having fairly frequent ejaculations from either self-stimulation or sexual activity, it could be your body is releasing small amounts of this fluid, especially if you’re aroused by smthg - a picture, a movie, talking to someone you’re very sexually attracted to. This could be especially true if you’re relatively young - teens thru early 20s & beyond.
As far as controlling it, some guys just produce more of this pre-ejacukate, so there might not be much you can do to control it, other than increase the frequency of ejaculation. If you have occasional ‘wet dreams’ (nocturnal emissions), that could be another sign you might want to increase the frequency of ejaculation, thru self-stimulation or sexual contact...
In any case, this is not harmful in any way - if it’s bothering you a lot, just increase the frequency of ejaculations & that will prbly decrease the amount of this fluid you’re seeing...