spray (something) onto (someone or something)
To shoot a stream of some mist or liquid onto someone or something. My parents kept spraying bug repellant onto us whenever we wanted to go out for a hike. It got so hot that we had to spray water onto the road to keep the asphalt from melting.
spray something onto someone or something
and spray something onto direct a mist or stream of a liquid onto someone or something. Danny sprayed cold water onto the boys and cooled them off. Dan sprayed on some cold water. I sprayed the paint on and it dried almost immediately.