Fuck Kate first

I undressed myself quickly, my cock was already at full attention. When my boxers dropped and my dick sprung out, Vivienne gasped.

"Wow, it's big." She was staring at it and seemed seriously horny. "Come on, how about you finish Kate off first."
"Is she on birth control? Cause I got no condoms." I didn't really want to put a baby in her.
"I'm not", Kate replied shyly.
"Welp, anal it is!", Vivienne decided.
"I....I haven't done that before though..." Kate went red and looked down to the ground.
I looked at her. "I'll be gentle, I promise."
She nodded.

Vivienne turned Kate around, so that her ass was facing me. I moved my hands down her sides to her butt and squeezed them. Then I spread her cheeks apart and moved a finger around her asshole. I slowly caressed it and then just as slowly pushed my finger inside her ass. She moaned, so I continued moving my finger in and out of her asshole. She was very tight.
Meanwhile, Vivienne started to kiss Kate and massaged her boobs. She moved down to Kate's pussy with both her hands and then with her face, kneeling down and licking Kate's pussy.
Moving forward, I put my dick between Kate's asscheeks and started moving my hips, grinding my dick on her ass. Kate was now moaning louder and started panting. I put the tip of my dick up to her asshole and pushed slowly. The tightness of her hole didn't make it too difficult to enter her, since we were all wet from the water of the shower.
I picked up a pace, starting slowly to move my dick in and out of her asshole, then getting continuously faster. I was fucking Kate's ass, while she received oral from Vivienne.

She didn't last long. Kate started moaning louder and more often. I sped up one last time, squeezing one butt cheek and slapping the other. Then she came. She was shivering all over, moaning loud, pushing Vivienne into her pussy. This was enough to push me over the edge aswell and I came in Kate's ass. Hard. I pumped as much cum as I could in her asshole. We were now both panting and moaning.

After all of my cum was out of my dick, I slowed down and pulled my dick out of Kate. The cum that was dripping from my dick and her ass was washed away by the water immediately. Kate slumped down to the ground, completely out of breath.

"So", Vivienne spoke up. "That was tasty. Now what about me?" She looked at me with lusty eyes.
"I just need a second to get hard again. And catch my breath", I replied.