It depends. Sometimes a little LITTLE bit of pain is actually enjoyable. I like when a girl sort of slurps up one or even both of my balls in her mouth, some guys will like that some won't. Licking the scrotum(ballsack lol) is also nice. The scrotum got lines on it almost like it is a burlap sack maybe trace along them with your tongue. Something the girl I lost my virginity did that I will never forget. We were having sex and I was doing her from behind and she reached back and cupped my balls in her hands. There was something very sort of romantic about it. All I can say is me and I think most guys like for a girl to pays some attention to our balls and not ignore them or be grossed out by them. They do look weird even we think so.