Family Ties/Going for a swim.
"How about we just go for a swim in the lake while the others are out screwing around." You suggest as your mother moves back to a standing position, running a hand through your unruly hair.
"Sounds good to me baby, I am already dressed for it." She giggles. "I just hope you can keep your hands off my pussy long enough for us to swim." Your mom doesn't exactly make a convincing case, not that you have any intentions of making any promises.
Instead you give her ass a pinch and head back to storage bin and grab your bag and pulling out your swim trunks, strip, and pull them on. As you are replacing your bag were it came from you glance back into the back bedroom noticing Heather's bikini bottoms abandoned on the floor, left there so she could make her pussy more accessible to your big brother.
After you're ready you walk back in the center of the RV and take your mother by the hand and lead her out and down to the lake. There aren't many people swimming today, with it being so early in the season. You and your mom wade into the lake where there aren't many people around and those that are aren't really paying any attention to you despite the revealing bikini your mom is wearing.
Once in the lake neck deep you are paddling gently in front of you mom and she grabs you and pulls you tightly to her body. Your cock is pressed against her and her tits are right against your chest as she stares lovingly into your eyes. To those watching you look like any other mom and son splashing around in the lake, having a good time. No one is the wiser that your mom has slid her hand up your thighs and into your swim trunks, squeezing and massaging you ass cheeks. Just under the water line you are squeezing her titties, making her moan and giggle and the two of you grind against each other.
"I knew you would be able to keep your hands to yourself." She says, Looking like she desperately wants to kiss you. "Well, I am not exactly behaving either huh baby?" You shake your head and under the water grab her bikini top, giving it a firm yank, splitting it so her tits spill out into the cool water of the lake.
"Timmy?! You horny little brat. Bad enough your father figured out how bad I want to fuck you.., I am not sure I could explain it to all these people." Despite what she just said she only squeezes your ass hard and pulls you deeper into her breasts. "I suppose if we were careful we could do something about that big bone of yours." She says with a naughty smile.
You could: