What does it mean when guys want you to sit on their lap?

This guy I'm dating asked me to when I hung out at his house. He's really sweet, mature and well mannered. But he's an adorable flirt. I felt kind of insecure because I'm kind of bigger than him haha. He's a fit, 6'1 baseball and I'm on the curvy, thick side. I'm 5'8. He told me he doesn't care but yeah.