Glans
The glans is the enlarged, sensitive tip of the penis. In an uncircumcised and non-erect state, it is covered by the foreskin; when erect, it is exposed if the foreskin is retracted. Because of its dense nerve supply, it is a highly sensitive organ and can be experienced very differently depending on the person.
In a BDSM context, the glans may be deliberately stimulated, for example through touch, friction, or controlled sensory input. Hygiene, a gentle approach, and the individual limits of the person involved are important, as the glans can be easily irritated or injured.