The Riding Lawn Mower
When you and your sexual partner are outside in a grassy area doing it doggy style, and the female orgasms, planting her face in the grass and effectively cutting it with her teeth. Process repeats in a new area, and the riding lawn mower is in action.
After they did the Riding Lawn Mower for a few hours, Andy and Vanessa could finally play soccer together on the newly cut lawn.