Is he touching his toes & feet yet? Maybe you could encourage him to play with his feet - and keep repeating a couple of words ("gentle" works for me, or "don't hurt mummy").

I find that "you hurt mummy" has been working since he was about 18 months old and then saying "hug mummy better". At six months, I don't think my son had any idea about consequences or pain or hurt ... so unfortunately, advoidance.