Take her into the water

You take her hand.

"Ready?" you ask.

"Sure," she says, blushing.

You lead her into the water, and swim out to join the other girls. Of course Riona's there, getting handsy under the water, and it's no coincidence when a lot of the other girls start swimming a little close to you and Riley. Your cocks brush them under the water, and the giggles are as loud as the splashing.

Riona can tell how interested you are in Riley, so she starts teasing Riley, getting her naked body close and distracting her. You swim up behind Riley, who cannot possibly turn any redder.

"Go easy on her," you say to Riona, hugging Riley protectively from behind. Your erection presses against her back.

"Don't hog her to yourself," Riona says, coming in and hugging Riley from the front... so now Riley has two sets of boobs up against her, and one big penis bumping against her rear.

"How do you like it here Riley?" Riona asks, seeing how overheated Riley is... it's like steam is going to come out of Riley's ears.

"It's great," Riley gasps. You start to reach around her, only to find that Riona's already fondling her cock under the water. Well... there is no escaping from Riona now.

"Give us a kiss," Riona whispers, moving in and kissing Riley before she can reply. Luckily it's dark, so nobody else is really seeing this...

"Don't leave me out," you say jealously, turning Riley's head so you can kiss her too. Her lips are soft and shy, but her tush clenches and feels amazing against the underside of your shaft. You hump against her and stroke her body as you kick your legs... Riley is not swimming at all, so you have to keep both of you treading water.

"Here darling," Riona says, grabbing you and nearly sinking you so she can cup one of her breasts and offer it to Riley, who swallows nervously... then wraps her lips around Riona's nipple. "Oh yes. Touch me." You can't see it, but you know Riona's getting Riley's hand between her legs now.

You feel Riley's boobs, which she must like, because she starts to writhe. From there it's just a tangle in the water until you feel Riona's legs clamp together, and something very warm in the water that you are sure is Riley's cum... then you're groaning into Riley's wet neck and bursting your load as well...

You help the lightheaded Riley back to the bank. Sharing is OK sometimes.