Okay, in order for me: Adam, Tom, Leo. >:D He can be an honorary member of the Inception RPF smorgasbord of beautiful people. If Joe or Cillian shows up, I might die of perv bliss. Damn it self, get Cillian/Domhnall outta your head.
(I have nothing against Oscar, but I've seen that pairing more than Domhnall/Adam. Granted, I haven't seen much RPF in this fandom whatsoever. I also have nothing against het, but the idea of that lithe Irishman being manhandled does things to me. I'm only half sorry.)

Also? I'll come clean: I wrote the threesome RPF misfire fill and the "ginger filling" TFA or RPF prompt. The latter is similar to this in fact, haha, I just realized. XD So Adam/Domhnall/Oscar and Tom/Domhnall/Leo are also on the table. (I mean, why choose, am I right? ...Fine, I'm mostly sorry now.)