Reality, or at least your perception of it, fades out as the chip dissolves into nothing more than a faint and vaguely minty tingle. Fading in to replace your surroundings is a comfortably close, gently-lit alcove. Probably someplace in Bottomwarp. From either side, there's the illusion of the twins leaning in and whispering to you. "Welcome." "To us."
A moment later your senses split, letting you see and feel Trancend from their own perspectives, letting you know just what it's like to be both of them at once. If you focus on just one set of sense-input, it becomes stronger than the other. Simply put: Choose a twin, feel what they feel. After you've made your selection, the recording seamlessly picks up where it left off.
The twins undress each other, letting you get a nice eyeful of their anatomy. Cend is quite attractive in her own right, without being overblown or misproportioned in any way. She's gentle curves and softly defined muscle tone, matched with a pair of modest breasts, the simpler pleasures of the feminine form refined.
Trans, while sharing the same general traits as his sister, is slightly 'harder' in appearance. It's obvious he spends at least some of his spare time working out, with a decently defined upper body and torso. Looks like he pays special attention to his lower body, judging by the extra definition around his thighs, calves, and butt. He's also respectably hung, bordering just this side of impressive.
The twins smile at each other, then sit down together against one of the alcove's curved walls, and begin masturbating. Nothing fancy here, just the usual stroking you'd expect from someone on their own, only doubled. This is prolonged for several subjective hours, but the twins have more than enough control to stay just this side of an orgasm the whole time.
Trancend pause for a moment and shift around to sit opposite each other, grinning, and then something seems to /twist/ in your head. Then they pick up where they left off, stroking themselves with a renewed vigor. Your senses shift and crosswire, feeding you everything but the visual from the opposite twin, allowing you to watch exactly what bits are being stroked or fingered.
Then they reach orgasm.
Cend squirms in place around her hand, fingers stroking inside and out of her dripping sex as she climaxes rapid-fire, at least thrice over before her brother goes off.
Trans' orgasm, while not quite as prolonged as his sister's, is quite impressive in its own right. There's a tight, swelling feeling during the buildup, like your pleasure center's been blocked up for some reason. Then someone pulls the plug out, and he goes off. Spectacularly, even. Excellent volume, velocity, and accuracy, and some decent splatter across his chin and chest.
Cend's body spasms a good three or four more times as her brother finishes, and with a smile, she settles back and idly strokes herself as Trans recovers.
The recording fades to black, and the black fades back to reality...