Smegma is a thick white cheesy looking substance that is a build- up of sweat, skin cells, natural oils and other fluids. Smegma is not an STD and it is not contagious.

It can commonly be found on the penis, and particularly under the foreskin of uncircumcised males.

It is normal to have some smegma, but if it is not washed away regularly, fungus and bacteria  can grow in it and it can smell really bad. It can also lead to painful conditions like balanitis and phimosis. 

If you wash everyday and there is still cheesy discharge or a bad smell, you need to see your doctor.