Often, but more regularly lately, I've had a fantasy that I'm dating a girl, we've been together for a while and so on, so forth.

Then, there's her little sister. A sweet, little thing, freshly graduated or in her last year of school (obviously of legal age.) She's a lot like her big sister, lovable for one, but small and fit for manhandling like her sister.

The difference is that she's shy, more reserved, and as a result: she's still a virgin.

Being the loving, caring big sister she is, my girlfriend wants to make sure her baby sis has a good first time, like she had with me. So, one night she invites her over to hang out at our place. What she doesn't mention is that it's all a rouse to get her laid.

After a little beating around the bush, my girl starts getting handsy with me, and I get handsy with her in exchange. Her sister watches in an awkward, jealous silence for a little bit before my girl pops the offer:

"You wanna try?"

She's reluctant at first, touching her sister's boyfriend, in front of her sister no less, but eventually she gets into it, and they're both touching wherever they can.

That's when the eldest of the two makes the next move, undoing my belt, popping the button on my pants, unzipping me and taking out my cock to give a few soft strokes.

The younger one relents a bit, but her sister coaxes her back in with gentle coos, assuring her it's okay to keep going.

Gradually, my girl decides that rather than just letting her sister feel me up and fuck me, she'll teach her directly, to show her all the things she should do. She teaches her how to kiss, letting her go at me a few times before interjecting and kissing her, herself. They suck my cock together, one on either side, their tongues meeting until the come back off only to get into a heated kiss. When it's time for the younger girl to ride me, her sister eases her in with some oral, first, letting our "baby girl" sit on my lap while she licks away at her pussy - something she'll teach her eventually.

When she's good and ready, I hold her tight and take control, then ease myself info her untouched hole. Her sister stands and watches, fondling herself when I let her, and offers encouragement for the little girl. "Good girl! Keep going! You make me so proud!"

Once they've both had a turn riding and cumming on my cock, they both drop to their knees to serve their shared Daddy with their mouths.

My girl lets her sister handle the main act of sucking my cock, while she puts her mouth on my balls and begs for cum.

When I do cum, I unload into the younger girl's mouth and she freezes up, having no clue what to do with a mouthful of cum. So, being a good sister, my girl steps in, grabbing her by the cheeks, kissing her deep and pulling all the cum into her mouth. Then, she swallows, smiles and gives her another kiss.

This becomes a regular thing, from that point on, and I sleep with both more or less evenly. The younger girl isn't interested in other guys, nor is her sister, so we have fun as the three of us. Out taboo, little triage.