Sirius Black's body was simply a wreak. Most men pray for the experience to come over summer. That way, one can easily lock ones self in a room or broom closet and cease to come out until transformation is complete. Much like a Butterfly.
But boys are not butterflies, they are human beings.
Though any adult would argue the pubescent male is FAR from human; Sirius was coming to gripes with his age.
"My knees hurt," he absently stated to Peter during Potions.
"Prof-FES-sor," croaked Black during Care of Magical Creatures.
"I can't feel my face," was said to Remus on several occasions. But the feeling of numbness on Black's part was not from puberty, but more so from the frequent sting of slaps received from girls after a remark about their bust size was mentioned.
This did not discourage Sirius, for he seemed to enjoy the pain.
...What a sauce.