Using a condom to only cover the tip of the penis, leaving the foreskin exposed. This is done to enhance pleasure for the male, by exposing the bundle of nerves where the foreskin attaches to the penis head. This provides the sensation of skin on skin, but allows the condom to function by catching the sperm. This does not protect against STDs and is not an approved use of a condom, but is used by many married couples who are unable to use other birth control methods and enjoy the skin on skin contact.
When I was shorting the condom, it felt like I wasn't wearnig one at all!