The main function of the foreskin in the male reproductive system is to protect the glans (the sensitive tip of the penis) and assist in sexual arousal. The foreskin contains many nerve endings, making it sensitive to touch, contributing to sexual pleasure. Additionally, it helps to keep the glans moist and prevents it from becoming dry and keratinized. In terms of hygiene, the foreskin can also trap smegma, which requires proper cleaning. Its presence or absence (as in circumcision) can have cultural, religious, and health implications.