The male prostate plays a big part in the sexual pleasure of a man. When you ejaculate, it travels up and around and through/past your prostate. Having your prostate played with is pleasurable for nearly every guy and the best way to access it is through the rectum.

Plenty of heterosexual men take part in anal sex because they enjoy the feeling. My guess is that this is the same for homosexual males.

When a male is the giver during anal sex, they can feel pleasure due to the tightness. When a male is the receiver in anal sex they feel pleasure due to the pressure applied to the prostate. Not to mention that on occasion simple and light rectal stimulation is also pleasurable due to the amount of receptors in that area