His coin flip told him to make the dice before meeting the person. So in inspiration he thought he'd put out his take on sex dice. Those dice you rolled where one had body parts and the other had acts such as: kiss, snuggle, bite, etc. One's that had you perform acts you may not have thought of. Instead he had decided on a more transformative approach. After all what was more spicing things up than changing the very factors of the sexual act themselves? Well there were probably many answers to those questions, but this project was ambitious enough as it was. Although there were two conditions he put on the dice. The First was that any transformations would be undone once all partners came at least once. Second no matter what the changes were all parties involved would find each other sexy... Would be a real buzzkill if they changed everyone into stuff they didn't find attractive and couldn't get it on... actually thinking of that. Third condition, subjects can cum not matter what happens to them. Alright now with those conditions that were not going to be circumvented in any way the Dice Maker could not have foresaw he went into his basement to make his Sex Dice!
...It took awhile but he enchanted them with so many effects... Too many for him to realistically explain but there were 2 dice that worked on a "weighted" system. It took whatever perversions the person rolling them had and weighted the effects to happen more often for that person with a random enchantment happening every now and again to really spice things up. Now the first dice would select some sort of aspect about their person. Their sex, weight, age, blood type, favorite ice cream topping, etc. The second dice would then choose a sort of change like swap, grow, shrink, copy, warp, etc.
The Dice Maker saved a blueprint for them as he was getting excited about these and rolled the dice about who he was going to give these Sex Dice too... They'd probably be some lucky bastard... Now who?
Now Who?