When I pull my foreskin down on the head is a bunch of white stuff. What is it and how do you clean it?
The head of your penis is called the glans. The white stuff you see is called smegma. It is combination of a waxy oil and dead skin cells. It's purpose is to keep your foreskin soft and flexible while at the same time trapping any foreign particles, like dirt or germs so they stay way from your skin.
Smegma should be cleaned off each time you bathe. You don't necessarily have to do a perfect job, but you should get rid of the excess. Not doing so can cause problems, such as the smegma drying down and acting like a glue between the foreskin and the glans.
To clean, pull your foreskin back so the glans is fully exposed. Then wash with warm water and a little bit of soap. Make sure you rinse the soap off completely as soap trapped under you foreskin will irritate it.
If you haven't been cleaning under your foreskin properly in the past, you might find some of the smegma has harden down and doesn't wash off easily. Don't try scraping it off because it will pull off some of your skin with it. Instead, fill a bathtub with water, pull your foreskin back and soak it for 10 or 20 minutes. If you don't have a tub, wrap a wet washcloth around the exposed penis. After soaking, use a wash cloth to scrub the area with soap and water. Then rinse thoroughly. It might take several days of repeating this process to get the old stuff off.
If your foreskin is glued down by the smegma, you can do the same thing to loosen the smegma. Pull the foreskin back as far as comfortable and then soak in warm water. Wash what you can with soap and water and then rinse completely. You can also loosen the foreskin by grabbing hold of it and pulling outwards as far as you comfortably can. See The skin on my penis doesn't pull back all the way to release the tip of the penis.