Initially, prostate stimulation might make you feel like you need to pee a bit, but this is just your body readjusting to a sexual response from stimulation.
It’s a gland that controls a lot of a guy’s sexual responses, and if it’s stimulated directly by having something push, rub or vibrate against it from inside the rectum it will blow more than just your mind. Hotspot number two, the prostate, is further inside - about a thumb’s length in towards the bellybutton.