Call the babystitter.

"I had no idea you were into this. Yes, please call Cindy over."
With that, your wife reaches for the phone and dials.
"Hello. Cindy? Hi, its me Diane. Yes, that's right. You know, I noticed how interested you were in our pool the last time you were here. My husband isn't home, and I thought you might want to enjoy it on such a hot day. O'K, I'll see you in a few minutes."
She hangs up, and expresses a sly smirk at you. You realize, its time to go hide in the bedroom. In a few minutes you hear voices, and then a door closing. You walk over to your master bathroom window and look out. Slowly, you hear the voices again and then notice the two females come into view heading towards the pool.
They are both in profile to your view, with your wife just slightly behind Cindy.
"Damn!", you think to yourself. "I've never seen Diane in that bikini. Did she buy that to entertain someone?"
"And Cindy. Her legs look great from here"
You then turn your attention to their conversation.
"You said your husband isn't home Mrs.P?"
"That's correct Cindy. And please, call me Diane. Here, let me help you with that blouse", as your wife reaches up and slowly pulls Cindy's blouse off her shoulders and lets it drop to the ground.
"What a lovely bikini you have on", your wife says. And you agree, because it barely covers the girl and you can see an ample portion of the right side of her breast. "Yours is pretty scrumptious too, Mrs. P..., er, I mean Diane."
"I think you need some lotion Cindy. Should I put it on you out here, or inside?"
"Well, Diane. I'm kinda private. Can we go inside to do it?"
Sure Cindy, I have some in my bedroom. Shall we go?.
"That sounds delightful Diane. Let's go."