Simplify the following text for a Grade 5 native English-speaking person.
Original: In male human anatomy , the foreskin is a generally retractable double-layered fold of skin and mucous membrane that covers the glans penis and protects the urinary meatus when the penis is not erect .
Simplified: The foreskin is a fold of skin that covers the glans penis . The foreskin protects the glans penis when the penis is not erect .