The actor was happy to pass on his experiences to 11-year-old Jaden – his son with wife Jada Pinkett Smith – but the young star insists he didn't need the advice.
He said: "My dad said, 'Don't kiss with your mouth open, you're definitely too young for that!'
"I'm good at kissing, so it wasn't as challenging as it could've been had I not had previous experience."
However, the 'Karate Kid' star admitted he didn't find locking lips as easy as he expected when it came to filming.
He told the Daily Record newspaper: "It was one of the most awkward things I've ever done in my 11 years of being on this planet.
"Our faces were like, this close, and we had to stay there so the shot was right. It's kind of awkward."
Jaden also admitted he had his mother – who also has a nine-year-old daughter Willow with Will – banned from the set of the film when he was shooting the romantic scenes.
He added: "She agreed to stay in the tent, because she knew that she would come out like, 'Jaden, what are you doing, boy'' "