What Causes The Urge To Urinate During Intercourse?

I am 19 and constantly have the urge to urinate during sex. I would imagine this is a problem... Even after drinking a large coffee while driving I feel that my Blatter is about to explode within no time. Any help would be greatly appreciated. I do drink a lot of water during the day and am a very active person if that helps at all. But even when I don t drink that much water, sometimes I feel the same way.