On her ass

"I'm getting close, Sarah. I want to cum on your ass."

"Anywhere you want, baby," she moans, slowing down. "We've got a pool to clean up in."

"Your ass. For sure."

She turns back and grins. "Then go for it." She lifts herself up, sliding off of you. She leans forward a bit, presenting her ass to you. You start stroking yourself while she watches, her eyes half-lidded as she comes down from her own orgasm. You're stroking yourself with one hand, squeezing her ass with the other and locking eyes with her. Especially after feeling her cum on your cock, it only takes you a few seconds before your own orgasm hits. You moan and spray your cum all over her ass and lower back. Drips run down through the crack of her ass.

"That was fucking hot," you say.

"Mmm, yeah it was." She looks over at the pool. "Let's get cleaned up before going back inside. I think I'll stay downstairs with you for a bit. I don't think I'm quite done with you yet."