Start pounding her as well

75% of your dick still hasn't experienced Melanie's asshole... And that's just not acceptable.

You pin her arms behind her back, and she falls forward onto her husband. Luckily, her large, mostly-exposed rack cushions the fall, which only turns Greg on more.

"Kiss," you order harshly, and Greg replies by pulling Melanie even closer, kissing her sloppily while forcing her tongue into her mouth. She returns the kiss, even while she gasps for breath.

The kissing frenzy pauses Greg's frantic thrusting long enough for you to grab Melanie's hips and push deeper into her mostly-untouched asshole. Greg's tongue muffles her scream, and you nearly orgasm then and there due to the feeling of her ass sheathing your cock. Her MILF butt is pressed so close to your own hips that you can feel the tight string that's splitting her asscheeks.

You and Greg are both pounding her now, although your manic thrusts aren't in time with one another. Melanie softly sobs and moans into Greg's mouth, overwhelmed by the unbridled lust of her husband and son.

Greg comes first, interrupting their kiss with a loud grunt. After grinding their hips together one final time, he collapses to the ground and allows his wife to pull back a little.

"Honey," she gasps, holding herself up as you keep thrusting into her ass. "Are... You... Almost... Done?" Every word is punctuated by a deep breath.

You are nearly done. Her thick ass feels far too good on your cock, and you can't hold out any longer. Like Greg you cum inside, filling her tight passage with what feels like a gallon of sperm. Finished and depleted, you slowly pull out... Which brings on a whole new wave of pleasure.

Once you and Greg have both extracted yourselves, Melanie flops to the side. For a moment you assume she's going to lie down and rest, but instead she stumbles to her feet. Staggering around like a drunk college girl, she tries to pull her bikini back into place. Even once it's straightened out, the ridiculous outfit does nothing to stem the flow of cum from her pussy and asshole.