Why is it when i masturbate and then stop without ejaculating i leak out white precum ?

Normal: Process is normal secretion of fluids from urethral lining and prostate as part of sexual stimulation prior to orgasm and ejaculation. Not to worry. Normal. But can also contain sperm cells that can cause pregnancy, so use condom to help prevent unwanted pregnancy and reduce risk of STD if engaging in sex. Hope this was helpful. Dr R