Dogs don’t usually exercise self control sexually, so it’s a lot more of a risk putting all of your tender human bits—like eyes—right in front of a strongly jabbing penis with a baculum inside it. You’d be better off, and safer, with the “suck” approach. Spend some time looking at good tips for male canine practices on here, and keep in mind you’ll want to provide the stimulation mainly by squeezing behind the knot and maybe with some gentle action on the tip, dog penises aren’t like human ones!