It’s all about the tongue.
You don’t have to be an adult film star to know how to use your tongue the right way. Flatten your tongue and pretend you are licking an ice cream cone. Then try the “pointy-tongue” technique to stroke up and down and side to side. Do different strokes and touches and pay attention to their reactions. When you find something that really gets the motor running, don’t over do it. You don’t want them to grow tired of it.