Triplet Idea

Okay so this is by far one of my weirder ideas but bare with me. The idea is our characters are triplets, 2 girls and a boy though I'd be open to playing a futa. The siblings are as close as can be, though they have a few secrets. The first one their family is all well aware of, MC was born with 2 fully functional cocks and 4 balls, it's something of a family secret but not one they're ashamed of or anything, just a unique quirk of birth. The second one is something only the siblings know, specifically that they've been fooling around with each other for years. Ever since puberty YC's, the 2 girls, have had a fixation with MC's unique physiology, at first it was just curiosity and some light teasing, but over the years it's gone much, MUCH further, to the point where the 3 of them are practically dating. To the outside world they just appear as loving siblings, but only the 3 of them know just how wild they get. 

It's pretty bare bones at the moment but I think it could evolve into a fun idea, I'm open to most kinks and would love to discuss this more.