Go for it.

"Jane? What are you doing down there?"

"Um... n-nothing," you stutter as you lower Krystle to the ground.

"Nothing, huh? Is this what you call 'nothing'?" Krystle reaches a hand around you and makes a grab for your ass. You instinctively twist away, and her hand goes right between your legs!

"Oops!" Krystle says, jerking away reflexively. "I'm sorry, Jane!"

"Oh, you're going to get it!" you shout playfully, and rush forward to grab her. Krystle turns and runs, but you're faster than she is. Soon you've caught her in a bear hug, and she squeals as you both slide to a halt, barely keeping your footing on the wet grass.

Having grabbed her from behind, you realize that you've got one hand on each of her firm tits, and the cool rain has made her nipples poke out against your palms. Krystle notices as well, and she takes one of your hands and moves it slowly back and forth over her own breast. "I can tell you liked the way my ass felt," she says. "How does this feel?"