I'm sure that you have met someone that has the hardest time trimming their dogs nails. Sometimes to the point that they become outrageously overgrown. Unfortunately, for dogs this is extremely uncomfortable and can easily lead to infection. Also, this situation is completely avoidable! If you have a puppy there are quick and easy steps you can take while your dog is young to make all of your grooming needs a breeze for the remainder of your dog's life.
Firstly, you should touch your puppy all over every single day. Touch their ears, tails etc. If you do this everyday until they are a year old and then intermittently afterwards, then there is no reason for them to be uncomfortable when the vet does it or even when a small child ambushes your dog.
Cradling in particular is extremely helpful for nail trims. When cradling sit flat on the floor, legs straight out in front of you. You should have your puppy belly up between your legs. Hold them firmly so they cannot wiggle out. Never let your puppy wiggle out from a cradle. The first couple of times you do this let them go as soon as they relax. They most likely will throw a tantrum and that is absolutely okay! Just wait for it to pass and then reward that good calm behavior by letting them up from the cradle. Slowly increase duration until your puppy is absolutely comfortable in the cradle. From here you can begin to start touching paws and tails. Make sure to give plenty of treats when your dog is being good in their cradle and when they are comfortable with you touching their paws.