WAUWATOSA - Was it a harmless birthday prank or a mean-spirited assault? That's the question after a group of boys in a 6th grade gym class punched and slapped another student on his birthday. Some of the boys say it's become a tradition for the last hour gym class at Whitman Middle School in Wauwatosa. Roberto Velez says a couple weeks ago, he received his "birthday punches." “It’s meant for something to be fun, not to hurt kids," Velez said. He estimates 16 or 17 kids in his class took a swing at him. It only hurt a little, he says. Still, Velez says it went too far on May 7, when another 6th grade classmate had his birthday. "It just kind of got taken too far and he got hurt," Velez explained. According to a police report, the boy expected to get punched at school on his birthday. That afternoon in the locker room, several of his friends punched or slapped him lightly on the back or shoulders. He told police it didn't really hurt. Several witnesses say another boy punched harder than the others, repeatedly slapping the 6th grader in the same spot. When the victim walked out to the pool, he had welts on his back and was bleeding a bit. He told the teacher it wasn't a big deal. She called the principal who later called police. Several of the boys admitted their mistakes immediately and apologized. The 6th grader who allegedly stuck the victim the hardest did not. He was booked on disorderly conduct charges and ordered to appear in Children's Court. He has also been suspended, according to friends.