Nope, they're still too reticent

You watch until two dresses lie puddled on the floor, but their owners continue to gyrate seductively, caressing and proffering their immaculate naked bodies to your hungry gaze.

"Oh, come on," you exclaim, exasperatedly. "Don't be so prudish. You know what men want to see from two girls together."

They gasp and stare at you, incredulously.

"B-but we're sisters," they blurt out in almost perfect unison.

"Well, you're only going to be acting, aren't you? It's not as if most women who put on lesbian sex shows to titillate their fellers are actually into each other. I'm sure Simon has perfectly normal faux-twincest fantasies like any other man."

For his part, all Simon can do is nod, eyes never wavering from the blondes' flawless curves.

With **** but to skirt the fine line between eroticism and **** under your greedy gaze, the girls turn back towards one another, gulp nervously and then haltingly, gingerly, shyly, go in for a kiss.

When their lips touch, it's as if a dam has broken. Almost immediately, they press their bodies together, boob to boob, crotch to thigh, moaning and kissing apparently passionately, although you suspect they're not actually using tongues. Closing their eyes (perhaps to make it easier to forget who their partner is in this little tableau), each runs her hands over the other's body, no longer tentative, but squeezing bum cheeks and rolling nipples between elegant fingers. Astrid (probably) starts to kiss her way down her sister's neck, while Alice moans in simulated passion.

She gets as far as her sister's breast, sucking her pale tit flesh into her mouth, before they swap and Astrid hops up onto the table so her twin can run her tongue down between her globe-like boobies and around her belly button. Astrid lies back, careful to avoid the teacups and milk jug, turning to look first at Simon, then you, when he fails to meet her gaze. His eyes are, understandably, fixed on Alice's crotch, which is perfectly angled for his delectation as she bends over to kiss her way along her sister's thigh towards the perfect pink flower of her sex. You notice, but maybe he doesn't, that neither twin is in the slightest wet, despite the stimulation.

Just as she reaches the apex, Alice (you think) pauses, thumb and opposing middle finger spreading her twin's labia, whilst her index finger pulls back her clitoral hood. She takes a deep breath, perhaps to prepare for the enormity of what she's about to do, but you're saved from the necessity of contemplating when a performance morphs into actual sex when Simon gives an almost pained groan and all three of you look to see that he's really quite red in the face. Alice changes tack without a second thought, backing up to sit on his knee and turning her neck to kiss his cheek while reaching behind her to unfasten his fly.

Your pants are also feeling quite constricting, which is why it's a good job that Astrid jumps off the table to kneel before you and free your manhood, which she takes smoothly down her throat, cupping your balls in one hand whilst her sister rides her date beside you. You're not totally surprised that Simon yells out in climax just a few seconds later and you glance across to see that he's crying with the intensity of his orgasm, his young lover mooning adoringly at him over her shoulder as she grinds gently to avoid overstimulating his sensitive cock.

You could cum now (Astrid's ministrations are truly superb), but your need is not so urgent that prolonging the encounter is out of the question. You'd quite like to see Astrid sucking Simon's spunk out of her sister's twat, for a start.