Just let MC control the clones mentally or something like that, and make it avoidable, too. That's it. This is not going to sit well with the "sharing" crowd, and the vanilla crowd may not like the extreme play. I'm generally ok with using super powers during sex though, so I give it the ok if they're literally an extension of MC. I don't have a twin brother so I can't exactly relate to that argument, lol.
And yeah, you can arguethat the LI is a slut for getting off to more than 1 dick, but someone said "sex toys" would've been ok along the multiple penetration tag, but that still ameks the LI kind of a whore ngl.
Honestly, it's just a dude using his powers, getting his girl off, that's it. Just make it soit's a hive mind and that's it.