Pet Mouse Pees Blood Loving Mouse But Only Pees On Me!?

Loving mouse but only pees on me!? - pet mouse pees blood

ok heres the story (LOL) I house mouse about 3 months. I've had since I was in front of their eyes still open spread. hes very friendly and cordial. Every time I close to his cage was excited and jump right into my hands, so kisses, but he pees on me (LOL) every time, if not ever! All this is why I do it?