Use your fingers

You slide your hand along her thong, teasing her crack. She moans and starts to wiggle her hips on your lap. You pull the tiny fabric of her thong aside, exposing her asshole. Licking your finger, you slowly play with her opening, running little circles around her asshole.

It seems almost more than she can stand and she slides a hand to her pussy, rubbing her clit while you finger her asshole. She moans loader as you slowly penetrate her ass with your slippery finger. She pushes back against your hand, almost asking you to fuck her ass with your hand.

You oblige. Now at a much faster rate, your finger is buried into her ass as she fingers her pussy.

"Give me more," she says.