The invitation is all he needs, in this instance. A power still not entirely understood, emotions too loose and needy to be restrained. Tidus is accepted, and without any sense of balance or place in the world yet, it's as if his being is flung across to where it's being summoned -

Inigo raises his head, and the sun is blotted out - as Tidus appears. Without a brake to his acceleration, and so crashing right into the other guy, not even with an embrace to give to go along with it. A flash of Inigo in his eyes and shared with Esteban, until the world gets a bit topsy-turvy in the landing made.

'Landing', of two bodies crashing into each other. A dizzying moment following in Tidus's head, but even with a brain empty of thought, his body trying to right itself where it's landed (where? on top of Inigo? In the dirt?, he's searching for places to put his hands and to pick himself up), Tidus still says, somehow:

"Inigo-!"

His mind isn't completely empty, no. There's still someone in there.