Your dog reaches a lamppost and pulls hard to inspect it. Then there is another smell a few steps away. You want an easier walk, not a walk with no sniffing. Letting your dog explore suitable places can be part of the reward for moving with you.
Start in a quiet area with a secure, comfortable harness and an ordinary lead you can manage. When the lead goes slack, say a simple cue such as "go sniff" and walk together toward a safe patch. If your dog surges and the lead tightens, pause where it is safe, give them a moment to reconnect, then move when there is slack again. Do not use this stop-and-start routine beside traffic or when your dog is frightened, change the route first.
Put sniffing in the plan
Give a few minutes for unhurried exploration before asking for a short stretch of walking together. Reward your dog for moving near you, then release them to a smell. Keep expectations small: a few easy steps are enough at first. Vary the release point so the dog is not always pulling to one exact landmark.
Some scents are not safe to approach: rubbish, food scraps, other dogs who need space, or the edge of a road. Turn away early, using a reward or a practiced cue, rather than wrestling at the last second. If your dog is so driven toward scents that you cannot hold them safely, get in-person help from a qualified, reward-based trainer.
A calmer lead can still take your dog to interesting places. It simply stops the lead tension from choosing the route. For more on making room for safe sniffing, see the sniff-walk guide, keep the lead slack and choose safe places to explor
Sources: Dogs Trust: Teach your dog to walk nicely on a lead. Dogs Trust: Dog walking problems and pulling on lead.