"Oh my god, what have I done?" Groaned Tim.
I wasn't about to allow this to just fizzle out and let Tim off to wallow in his guilt. He was nineteen for gods sake and knew what he was doing. This needed some proper management and I also had a mental image of Tim's large prick buried in his sister's hole that I wanted to see for real.
"You've just cum in your sister's mouth," I stated, "and I don't believe the sky's fallen in. Now I think it only fair you return the favour, don't you think?"
"What do you mean by that?" Tim sounded shocked.
"Well Tim, you're the only one who's cum around here. Do you think that's alright? It's time for payback, my lad."
Tim still looked quizzical. It was going to be a step by step telling him what to do. I knew that this could well work to our advantage.
"Have you ever wondered what Jan's firm little tits feel like?"
"Of course not, she's my sister." Snapped Tim.
"This is the same sister who's mouth you've just spunked off in." I scolded reaching out to grab one of his hands. "Feel her lovely firm breasts."
I pulled his hand down and placed it on Jan's right tit and started him off squeezing his hand around the firm flesh through her bra.
"Take off your bra, Jan," I told her, "let him feel your naked tits."
Jan reached behind her and unclipped her bra. She looked up at me for an instant and it was difficult to gauge what she was thinking. She slow let the material drop away from her little white breasts, her rock hard nipples and large dark aurole.
"Both hands." I instructed Tim.
He reached forward to start fondling Jan's breasts with both his hands crushing his wonderful erection against his tummy. He seemed awkward at first but gathered more confidence as Jan started humming pleasurably as the sensations spread through her.
"See how you've made your sister's nipples all stiff and hard. Play with them, Tim. Gently squeeze them between your finger and thumb and pull them a bit." I urged.
I found myself licking my lips as I watched Tim roll his sister's long hard nipple between his finger and thumbs. Jan looked up at me with a 'you bitch' expression on her face. I looked back with a 'you wanted to do this and you're loving every minute really' expression on my face that made us even.
"Why don't you get down here and use your mouth. I'm sure Jan would love to feel your tongue against her nipples and your teeth gently biting on them." The last bit I knew to be true as she told me once while I was sucking on them.
Tim just looked at me incredulously. I could see his cock straining and pulsing and knew how turned he was getting; he wouldn't need too much persuading.
I ushered him down onto his knees in front of his sister. Reaching behind his head I guided him down until his face was level with her small breasts.
"They're lovely, aren't they?" I asked him.
"Yes, beautiful." He replied as if in a dream.
"Suck them." I urged
I saw him look up at Jan as if to get her permission. Jan reached round the back of his head and pulled him forward and then she too urged him on.
"Suck on my nipple, little bro. Suck them like I sucked your lovely big cock." With that she gave a last tug on his neck and he latched onto her rigid right nipple. She made a strange groaning sound through gritted teeth as he started to pleasure her.
It was all I could do to stop myself leaning forward and taking the other in my mouth but I thought that might be a little too much for the boy. Instead I watched while he first laved one nipple then moved over to the other while Jan continued to hold him close to her and moan with pleasure.
I let him continue for some time and watched until Jan's hips started to thrust forward trying to get some pressure against her crotch. I've known Jan to cum by by sucking her nipples and I knew she was starting to build up to it. It was time to step things up a notch.
"You're doing so well, Tim," I told him, "I do believe you sister is getting very turned on by her little brother sucking at her tits. I think her cunt will be very wet by now. Do you want to see your sister's wet cunt, Tim?"
Tim pulled away from Jan's chest and looked down at her knickers.
"You'll have to take them off if you want to see her slit, Tim." I smiled then to Jan I said, "Stand up over by the bed Jan. I think Tim wants to take down your knickers and look at your cunt."
Jan was rubbing her suddenly ignored tits and looked across at me, then at Tim.
"Is that right, Tim? You want to look at my naked pussy. You are a naughty little brother, aren't you." She teased.
Tim looked suddenly embarrassed and I saw Jan realise she might have gone too far. She quickly dived in to save the situation.
"Come on, Tim," she said as she stood up and wandered over to the bed, "come and take my knickers down. See how wet you've made me."
I gave Tim a little nudge in her direction and he walked over to her with his stiff prick waving about in front of him. I could hardly wait to see it buried in Jan's hot little hole.
Jan reached forward for Tim's hands and placed them on the waistband of her knickers on either hip.
"Pull them down, Tim." She purred. "Pull them down and look at how wet you've made me."
Tim hesitated for a second then slowly started to pull down her sister's knickers. He watched fascinated as they peeled away from Jan's shaved slit and his eyes never left it as he pulled them down to her ankles. Jan casually stepped out of one leg and flicked the other foot so the knickers kicked up in the air. She deftly caught them with one hand.
She moved them in her hand until her finger and thumb rubbed over the crotch of the silky garment.
"Mmm, they're a bit damp and slippery." She said almost to herself then she raised them to her nose and sniffed noisily all the time keeping eye contact with Tim.
Tim has knelt down to take her knickers off and was looking up at Jan as she spoke. He watched wide eyed as Jan lowered her knickers from her nose and pushed them against his own face. He had to breathe and took in his sister's feminine aroma.
"Can you smell her cunt, Tim?" I asked.
Tim nodded and his prick gave a little jerk.
"Why don't you touch it?" I added. "Slip your fingers into your sister's hot sex."
I saw his hand twitch by his side then ever so slowly he raised his arm. His hand made contact with Jan's leg just above her left knee then started to travel upwards. Jan's legs parted slightly as her brother's hand neared the top of her leg. She was breathing heavily.
She gave a little cry as the edge of his hand slid against her sex which led to a little gasp as he ran the edge of his finger along her slippery slit.
