Randall offers his body up as a masturbation aid

You couldn't meet Randall's gaze, feeling far too embarrassed to see your mother's face staring at you with you still-erect penis sticking halfway out of your trousers.

Randall walked over to face you, his grin turning into a more thoughtful expression. "Come on, Tim, don't be like that," he said in a half-pleading, half-joking tone. "Tell you what, let me make it up to you. I'll give you a little show to help you out - I know you don't ever get to see boobs like this close up."

With that he unbuttoned the front of his blouse and pulled it off. You looked in shock at the image of your mother standing in front of you in only her jeans and bra. Randall was of course wearing your mother's undergarments - nothing overly sexy, being her typical white, conservative bra made for support rather than show. You hadn't seen your mom like this since accidentally walking in on her changing a few years back. You still felt a phantom tingling on your cheek where she had slapped you.

Before you could say anything, Randall reached around his back to unfasten the bra, then wriggled free and let it drop to the floor. Your mouth dropped open in shock and amazement as you found yourself gazing at your mom's rather sizeable bare breasts. You were dumbfounded. While you had got to second base with a couple girls, none of them had breasts like this, not even half the size of your mother's. And you couldn't believe how amazing they looked for someone her age - still mostly firm and rounded, with her creamy skin showing very few age spot or veins.

You knew you should look away or tell Randall to stop, but you were so taken off-guard that you couldn't really respond. He wriggled his upper body, making his breasts shake and jiggle. "Aren't they something?" he asked. "I can't get enough of this."

He put his hands under his breasts and lifted them up, continuing to jiggle them. Then with a sly look, he pulled the left one up and bent his head. You gasped as he teased his nipple with his tongue, then inserted it in his mouth and slowly sucked. You felt ashamed and a little disgusted at yourself for watching your mother like this - but you were even more aroused. You had never seen anything like this in real life, and you couldn't stop watching. Your penis throbbed so you had to pull it back out of your pants to relieve the pressure, letting it spring fully erect.

"Gah...duh..." you started, unable to form words. Finally you blurted "Randall! God, what are you doing?!"

He stopped sucking and lifted his eyes to meet yours. "Relax, dude, I'm just giving you a show! Sit back and enjoy it!"

And with that he started on his other breast.