i mean really, if the dog is worth its salt this will all go away when you start marking the dog out.
Stepping on toes? Really??? A dog leaning on you is dominance so beat them? Geez, Louise. In fact, leaning is most often a sign of submissive, "clingy" behavior. I've seen it far more in the dozens of abused rescues I've trained than in truly dominant types that tend to try to be much more independent. Proper leash mechanics and well executed corrective turns will correct this problem. To do this, you trap the leash with your left hand (which should ordinarily NOT be on the leash) about 12" from the snap. You do this to stop the dog's forward momentum then immediately turn 90 degrees INTO the dog, putting your thigh on the dog's neck and step through him. This is so you can turn his head to your new direction. It doesn't take many abrupt turns like this for dogs to realize you could turn at any time so they separate from you and are prepared to pivot out of your way. You also don't risk broken toes. SHOW the dog how to be right.
Wow, y'all really didn't care for the stepping on toes comment or Wayne's heeling stick suggestion. Yes, shaprly turn into the dog when doing heeling drills. What happens when you do this??? They often will get a leg pushed into them...or maybe a knee....ergo my suggestion of kneeing the dog. Furthermore, I wasnt implying to stomp on the dog's toes, but if the dog is leaning on you while you walk, another thing you can do is to step on his/her toes (dont STOMP them) and it will move away. Useful if he leans on you while sitting at heel. A swat with a heeling stick would do the same thing...Not so much a difference to me as using a pinch collar as some have suggested. It all make the dog associate that being on your leg is uncomfortable.