When Nate’s dad gets home from work, Nate runs to him shouting, "Daddy!" His dad sweeps him up in a bear hug, gives him a gentle knuckle rub on top of his head, then lowers him to the ground in a pretend choke hold. Nate screams with delight, escapes the hold, and climbs on his dad’s back to ride him like a horse. Inadvertently, Nate hurt his dad while climbing, and his dad said sternly, "That really hurt. Be nice!" What kind of lesson is Nate’s dad teaching him with this bout of rough-and-tumble play?