At first, Naruto just suggests it as a joke, and at first, Ino is completely put off by the idea, scolding him for even bringing it up. Of course, once he has assured her that he was only kidding, her mind starts to wander, and then she begins to seriously consider it, even though it had previously been unthinkable to her. And then, next thing she knows, she is bringing it up on her own, with Naruto barely able to contain his laughter, knowing that it is all because he put the idea in her head, and that, despite all her big talk, she is actually totally into it.
Which is how they find themselves in each other's bodies. Naturally, they have become quite familiar with said body, just not in this exact way. It is a more external familiarity, but that makes it every bit as exciting as Ino thought it would be, to be inside Naruto's mind, looking at herself, helping herself out of her clothes. Finally, she gets to see and feel things the way that he does, gets to see what it is like to fuck herself, in a sense.
How could she not get all riled up just thinking about it?
Ino pins Naruto down to the bed, and to an outsider, it would look like the exact opposite. She holds his- her own- hands above his- her own- head, and leans down to kiss him, able to feel just how soft her lips really are as she grinds her- Naruto's- cock up against him. He is so wet for her, or she's wet for him, and thinking about it too much makes her head spin, even as the master of this technique. The only thing that she wants to think about right now is fucking him, as hard and as fast as she can, for as long as she is able to stay inside this body.
She thrusts forward, immediately overwhelmed by how tight he is, how tight she is. If this is what he gets to feel every time, she can understand why he goes to pieces so easily. This is more intense than anything that she has ever felt before, further confirming that men really do have all the luck. Not that she has ever gone without pleasure, and it seems like a case of the grass always being greener, because Naruto looks up at her with her eyes, and bites her lip, and whimpers, in her voice, that this is the best thing that he has ever felt.
And she is just getting started. Once she starts pounding into him, they are both completely lost in it, and both so overwhelmed by it, so certain that they will never feel anything better than this. It goes without saying that this is not going to be the last time that they swap bodies, not the last time that they want to see things from the other's perspective.
As far as Ino is concerned, she might never tire of this