P-spot
From wipipedia.org

The P-spot is a supposed analogue among males of the G-spot for females. P stands for prostate gland. The P-spot is located roughly two inches into the rectum on the front wall.
Stimulating the P-spot has been claimed to elicit intense orgasms and is best accomplished by inserting a finger or vibrator into the anus and pushing gently toward the front of the body. This stimulation may account for part of the pleasure of anal sex.