What does it mean when he playfully touches me?

Not in an inappropriate way, but more of a playful flirty way. What happened multiple times was, In class when he asked me for gum, he rubbed my back and shoulders, I guess you could say in a "seductive way". The next time he asked for gum, he rubbed all up and down my thigh and inner thigh. oh he tries to tickle me by poking my sides, and squeezing my leg. and he has a girlfriend for about 7 or 8 months now... oh, and we also have a recent history of flirting quite a lot. WHY DOES HE TOUCH ME LIKE THAT IF HE HAS A GIRLFRIEND?
What does it mean when he playfully touches me?
Post Opinion