Hey all, I'm looking for a stories where the parents have sex on the same bed or same room as their son. The story should then expand into the son getting involved. Anything of this sort would be highly appreciated or just stories that involve mom son and dad.
So, it starts with the parents cuckolding the son? I cant' imagine a scene progressing from the one to the other in any remotely natural (i.e. believable) progression.
There are variations though, say if they're stuck in a single room or on a camping trip, where you can't help but notice what you can hear or the shadows you can easily observe given the lighting. Yet that's hardly the same premise. The first sounds like a tease, whereas if it's accidental, then the son would be naturally interested in 'seeing' more, even if they never dreamed of diving in head first. Thus any further escalation would progress from that initial attraction/involvement.
Again, one is too 'in your face' while the other requires a bit more subtlety. But essentially what you're looking for is an incestual threeway, with the resulting m/M tag as well?
There are a lot of assumptions to your proposal which you may want to pinpoint/outline a bit.
But even in exposed to something like that, just climbing into bed with already committed couple is a stretch too far without some further encouragement of some sort. And often, this takes the form of the father, encouraging the mother into seducing the son so he can watch, getting off on the incest while not actively committing incest himself.
Again, a major limitation is the response most MM or Mm stories receive on SOL, so simply to get a decent score, they'd have to intentionally soft-peddle such a response. (i.e. making it lurid, not actively gay.)
The other alternative is for the parents to expose their lovemaking before subtly suggesting the son get involved with his sister, who then later joins the parents, once their inhibitions have been suitable lowered. Alcohol is always a handy way or crossing that particular barrier.
Still, it's hard to have a serious incestuous interlude without any real intimate encounter, as a 'hot orgy' is anything but 'intimate', as you're just leaping on anything which is available at the moment. Ugh!
So again, decide in your into a mini-orgy scene with all that entails or an intimate incestuous encounter where there's a mutual attraction propping up and justifying their actions.
Otherwise, an alternative is a 'forced rape' situation, where a rapist forces a family to engage in incest, and who then shelter each other in the aftermath—often freezing out anyone (i.e. the father) who took a particularly intensive interest (i.e. non-sympathetic) response.
Yet your "should then expand into the son getting involved" indicates this is more aligned with your own interests. So less incestuous orgy and more of a natural progress of desires. More nuance than sheer kink.