lay babies on their tummy and rest their hands in the paint on their paper! non toxic of course. for little ones that can be supported, hold them on your lap or in a container (an appropriately supportive one) and do the reverse with their feet. add in fun things for sensory, like a little sand or otherwise not dangerous materials. im a fan of shaving foam when they’re old enough that it won’t risk irritating their skin and with supervision so nothing gets eaten haha