Semen production goes on in the testis for 24 hours and gets stored in seminal vesicles. Now imagine seminal vesicles as a water tank. 24 hours production at some time, will make tank full. Its storage capacity runs out. Now overflowing mechanisms take place like premature ejaculation,night falls and seminal discharge in urine. To avoid this u need to have sex or masturbate regularly.
Next Steps
Masturbation is healthy process.
Penis is made up of muscle tissue and masturbation is an exercise for penis to strengthen it.As you are doing exercise in gym to strengthen your body muscles...
Whenever you are doing sex,semen discharge from penis occurs as if you do in masturbation.
Difference : in masturbation,you are using hand and in sex it is done in vagina.
Once in 2 3 days is normal,but more than once in a day is harmful.