I would like to tell you the affect of over masturbation both physiologically and psychologically. Before that, let me clear up what masturbation actually is.
So masturbation is stimulation of one's own genitalia till the point of orgasm. It can be achieved through your own hands, partner's hands or body parts (except penetration in vagina) and through inanimate objects (in our case: balloons).
Yes, masturbation is a healthy practice and keeps your body away from groups of diseases such as uterine tract infections and as per research, prevents prostate cancer too.
Masturbation is equal to having sex; the only difference is you are not penetrating into a female vagina. A person can have sex daily, so as is masturbation......but, too much of anything has never benefitted anyone

Now let me tell you abt the physiological effects of over masturbation:
1.
The quality of semen falls down.
U might have noticed how masturbating too much in a day makes ur semen thinner and watery. This shows that your accessory glands (prostate, seminal vesicles, etc) are now fatigued and needs rest. And if continued for more than one day, can cause pain in the glands which is uneasy.
2.
Erection is affected.
Daily masturbation won't keep your stick upright always XD. There will be a time where it will get fatigued and it will be "semi flaccid" or completely "flaccid" in extreme cases. Hence, penis will not see the blood flow needed for the maximum erection possible. If faced by such problem, just give a gap of at least 4 to 5 days rather than searching for stuff which can make u jerk off more. Certainly you don't wanna end up being soft down there when u hit a score with a chick
3.
Pain in buttocks and thighs
Sexual activity requires contraction of certain group of muscles which enhances the simulation and helps in reaching orgasm. Thigh muscles and buttocks become contracted while u orgasm. But, since they are muscles, they are prone to get fatigued which can result in pain and strain. Again, give a gap of decent amount of days to regain the fun.
4.
Problem in holding urine
As u over masturbate, the group of muscles get fatigued and u will face problem holding ur urine. This can result in embarassing situations. Since there's only a single passage for both urine and semen, hence the group of muscles are also same. Sphincter muscles or valves of ur tract if fatigued will get u leaking down there....and nobody wants that to happen right?
5.
Prone to infections
Over masturbation certainly makes u overlook the hygiene thus inviting infections on the way. Semen is high in fructose sugar which is a major food source for numerous microbes and fungi. If u are uncircumcised, the risk is more as the foreskin can trap some semen. Even slightest amount of semen around the penis or around the groin area can lead to jock itch, ringworm, rashes, and even worse...UTIs.
Now moving on to psychological effects of over masturbation:
1.
Addiction
Since it's cited by many looners above, I won't elaborate.
2.
Distaste towards actual sex
Over masturbation can cause u loving your hands more than the real deal, which is penetrative sex. This particular thing has devastated a lots of relationships.
3.
Lack of enthusiasm and joy
Over masturbation makes u think that this is the only fun thing in your life. Hence, whatever comes forth seems as uninteresting and u again resort to masturbation.
4.
No clarity of thoughts
Over masturbation can make someone think all day long about it and hence, cognitive functions are affected. Prolonged practice can result in degradation in being out of focus everytime.
5.
Social behaviour is affected
Over masturbation affects the way u interact with your friends and family. The only thing going on in the head will be masturbation and ur brain will try to find various means to jerk off. U will try to not engage any type of social interactions and hence it degrades our psychology because afterall we are social beings right??
I may have written a long post, but it will help you understand and get a deeper insight on the over masturbation.
Remember, nothing is too much until it starts to hurt u!
Regards