Smegma is simply the accumulation of dead skin cells that are normally shed from the glans and lining of the foreskin throughout life. Do not use soap or leave soapy water under the foreskin because this can cause irritation and swelling. After cleansing, always pull the foreskin forward to its normal position. Retraction is excessive if it causes any discomfort or crying. By the time your son is 5 or 6 years old, teach him to retract his own foreskin and clean beneath it once a week during baths to prevent poor hygiene and infection.
Gentle reminders are necessary in the early years.
In summary, foreskin retraction is overdone in our society. Keep in mind that any degree of foreskin movement is normal as long as your boy has a normal urine stream. There should be no rush to achieve full retraction. Full retraction always occurs naturally by puberty. As the foreskin becomes retractable on its own, your son should cleanse beneath it to prevent infections.