im a male 26 years old and sometimes experience a rather uncomfortable sensation after ejaculation. after i finish, a few minutes later i get a urgent need to urinate. and then i go to urinate and nothing comes out... this lasts for usually 30 minutes or so. also my penis never gets completely limp during this time. its semi erect still. the urgency to pee is very annoying and usually prevents me from sleeping for quite a while. it feels as if my bladder is full and if i dont get to a toilet to pee right away im in trouble, but when i get there i don't have to go.... this dosen't happen everytime i ejaculate but it seems to be happening more frequently the last month or so. any ideas whats going on here?