(Rui x ???) Who would make eat Lettuce more- Tsukasa, Nene or Emu?

Imagine this: Rui is dating one of his unitmates and the couple didn't kiss yet + Rui needs to eat veggies but is refusing to do so, their lover so decide to kill two rabbits with one stone by putting a leaf of lettuce in their mouth, making it so that rui would only manage to kiss them if he eats the lettuce until they arrive into their lips.

Who would make Rui actually kiss them if they pulled this off: Tsukasa, Nene or Emu, and if not, what Rui would do to outsmart them in that scenario?