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The normal amount of fluid ejaculated can be anything from 2-5 ml.If you are not circumcised then few drops of semen as well as few drops of urine gets deposited between the glance and the skin above .This gives rise to collection of white residue called the smegma
.This is normal for any person who has not undergone circumcision
so no need to worry.Maintain cleanliness & there should be no problem if the skin just in case becomes irritated you can consult & ask a doctor
to prescribe some medicine.