Mom had planned on us getting back on the road after lunchtime, but Aunt Linda talked her into staying another night. I can't imagine Mom put up much resistance if she was promised a romp in the sack with her sister again tonight.
I returned from the store with a bag of charcoal, and food for a backyard cookout. I dragged an old grill out of the garage and rolled it around back, where I found my mom and Aunt Linda lying by the pool. They were stretched out on padded lounge chairs, both in two-piece bathing suits, chatting away merrily.
Mom must have been wearing one of her sister's suits. The top was too small and the bottom too big--an enticing combination. Their skin shimmered with a greasy sheen of tanning oil in the warm day's sun. I realized I was staring, and went about hosing the cobwebs out of the grill before my cock became hard enough to be obvious.
By the time I had the charcoal burning the ladies had turned over and were lying with their asses to the sun. Aunt Linda's top was nowhere to be seen, and Mom had untied the string across her back, but kept the top beneath her.
"Pool boy!" Aunt Linda called. "Oh, pool boy!"
I pulled off my sweaty t-shirt as I crossed the grass to where they were lying.
"Be a darling," my aunt pointed to a nearby bottle, "and put some sunscreen on my back for me."
"Ugh!" Mom rolled her eyes. "Could you get any more cliche?"
"You're just upset you didn't think of it first. Oil me up, stud!"
I looked at Mom, unsure if it would be okay with her. She just shrugged and gave me an exasperated 'go ahead' face. I poured some oil into my palm and rubbed it onto my aunt's back. She squirmed and moaned as my hands worked over her sun-darkened skin. Her lack of tan lines told me she spent a lot of time out here by the pool topless.
"My legs, too." Aunt Linda wiggled her butt suggestively. I knelt down and began at her calves, working my way up behind her knees, and finally to her ample, yet smooth, thighs. Mom watched me as I massaged the oil onto her sister's bare skin. She didn't look very happy.
As soon as I was done with her legs, Aunt Linda turned face up, exposing her bare breasts and fleshy nipples to me.
"Linda, what are you doing?" My mom's brow furrowed in annoyance.
"Oh, tish!" She waved off my mother's distress. "He's a big boy now. It's not like he's never seen a set of knockers before. Well, maybe not a pair this nice."
"You're impossible," Mom clucked and turned away.
"Besides," Aunt Linda motioned for me to continue rubbing the oil on her legs, "I haven't been touched by a man in years. You wouldn't deny your only sister this one chance for some cheap thrills, would you?"
Aunt Linda lifted her sunglasses and watched me rub her thighs with an expression of barely contained craving. When I worked my hand up the inside of her thigh, she double-checked to make sure her sister was still turned the other way, then pulled the crotch of her bikini aside revealing the shaven groove of her pussy.
Before I realized what I was doing, my hand bolted forward and I slipped an oily finger directly into her pussy hole. Her astonished face let me know she definitely wasn't expecting that, but her eyes told me she was absolutely loving it. Mom must have heard Aunt Linda's gasp and stifled giggle, and looked over to see what we were up to. I yanked my finger out of my aunt's bald snatch just in time.
"Am I being selfish?" Aunt Linda innocently asked my mom. "Do you want the pool boy to put some oil on you, too?"
"Are you even familiar with the word 'inappropriate'?"
"Speaking of inappropriate, don't forget the girls," Aunt Linda said and tweaked her nipples. "We wouldn't want these beauties to get sunburned, now would we?" I checked with Mom again, and she just rolled her eyes then closed them so she would see no evil.
I moved up and eagerly ran my hands across my aunt's soft breasts. Though somewhat smaller than my mom's, they were slightly firmer, but her nipples weren't as dark. I spread oil across her chest and in the shallow folds beneath her supple bosom. I noticed that my mom's eyes were open again, watching enviously as my hands fondled her sister's big, greasy tits.
Aunt Linda was lying with her head back, luxuriating in sensations of her breasts being gently kneaded by her horny nephew. My mom began subtly flexing her butt and pushing her hips downward. I could tell that she was pressing her mound against the cushion beneath her in an attempt to satisfy her mounting, unbidden arousal. I ran my fingers in circles around both my aunt's nipples at the same time, squeezing them lightly. This pushed Mom over the edge.
"Now that I think of it," she reconsidered, "maybe I do need some more oil on my back." Aunt Linda wore a Cheshire grin as I moved to sit on the edge of my Mom's lounge chair. Her muscles were tense when I first touched her, but within moments she relaxed and softened beneath my hands. She sighed with utter contentment, and once again turned her head away from her sister.
Almost as soon as Mom turned, I saw Aunt Linda sneak a hand down the front of her swim suit. She grabbed at her tits aggressively while her hand worked quietly between her legs. My aunt could easily see how hard I was. She nodded, looking meaningfully at my crotch, indicating she wanted to see more.
I used the moment when I moved from my mom's back down to her legs as an opportunity to snake my hard-on down the leg of my shorts. Only half of my dick was sticking out, but that appeared to be enough for Aunt Linda. She fingered herself briskly as she stared at the bulbous head of my penis peeking out of my shorts. I ran my hands up and down my mother's shapely thighs, barely able to contain my urge to shove my cock into my aunt's beckoning mouth.
I indiscreetly slid my hands up under my mom's suit and squeezed her ass cheeks. Surprisingly, she didn't react. As I withdrew my hands, I let my thumb slip into her crack and glide across her asshole. She flinched at that, but didn't say anything. Aunt Linda had seen what I'd done, and it was encouragement enough to bring on her orgasm.
She clenched her legs together, and bit her lip to keep from making any noise as she came right in front of me, without her sister having any idea what was happening. After holding tight to her pussy for several seconds she relaxed and licked her fingers, savoring the taste of her own juices. It was right about then that my mom turned over.