White layer is formed in penile shaft.

This is smegma trapped in the foreskin.Wash your penis with warm water and Dove soap.Remove the white deposit .If foreskin is very tight consult a surgeon.

I think it's just sebum Which is accumulated one needs to clean the penis with a mild cleanser like cetaphil during bath everyday which will prevent the accumulation and the smell. If you are finding it hard to retract is this a latest development or was it always like this? If it's always been like this a simple circumscision will relieve you immensely. Kindly consult a good urologist. If it's developed just now then try to very gently retract it while having a shower under warm water and try to clean up as much as u can under no circumstance should you be harsh to you genitals. These are our symptomatic diagnosis unless a physical examination is done we cannot ascertain, hence consult a competent urologist in your city. Don't worry and take care.