How to inject oil and air into a deadbait for Pike and predator fishing

How I inject oil and air into my deadbaits. I believe oil is best injected into the fish's anus vent, since it will push oil all the way through the tract instead of creating another unnesasary hole, meaning oil will slowly ooze out into the water. Ideally Inject air somewhere in the shoulder area, just in front of the dorsal fin - above the lateral line so the bait pops up head first.  Ps. Baits were in an old oily and bag with dye.