"He asks questions about it all the time so we had a father and son talk," Jackman told PEOPLE at a charity boxing match benefiting The East Harlem School at Exodus House in New York City Wednesday. "He knows about it but we haven't got into the intimate details."
The X-Men Origins: Wolverine star, 40, admits he wasn't uncomfortable during the conversation. "It's not awkward," he said. In fact, it was welcome: "My dad never ever did it with me so I was very adamant that I was going to do it with my son."
PEOPLE's Sexiest Man Alive says his best advice is to value the opposite sex. "You just got to respect girls," he told his son. "But he goes, 'Dad are they hot, though?' That's what he always wants to know."
And what's one thing to avoid? "I try to tell him that he not use me to get to them," he said with a laugh.
Expanding the family?With rumors circulating that he and wife, Deborra-Lee Furness, are in the process of giving Oscar and Ava, 3, a new sibling by adopting another child, Jackman confirms to PEOPLE that is false. "No, I'm not. It's rumors but we sometimes think about it," he said.
However, traveling with two children reminds him that a family of four is plenty. "Every time we get on a plane it's like the best contraception I know," he jokingly said. "So I think two kids is enough."
Cute CostarNow that he's conquered the box office with Wolverine, Jackman is set to star in the 19th-century drama Unbound Captives with Twilight's Robert Pattinson. "He's a really great actor and a really good guy," said Jackman. "His role is phenomenal and it's going to be really amazing stuff."
And what does he think about Pattinson's famous hair? "I'm not an aficionado of hair, but his looks great."