I figured that's who the player becomes during Natane's Stage. From what I could make of the dialogue it at least seemed like Natane was trying to teach a very young child how to type, and given that it ended in an H scene I kinda figured it was a child in a man's body, which would fit the description of the Green Boy. But then again I'm not quite sure what the deal is with the player character in Typing but it almost seemed like you're Quantum Leaping from one Viper series to the next and inhabiting the bodies of various other characters.
Now that I can see the pictures I can tell which endings they're from. JG00 was right about the first one mostly, although it happens just before the choice of whether or not to go into Namiki's room so that doesn't matter. So watch the shop until Natane gets the seed, don't show the seed to the sisters at the table, and later when Namiki approaches Natane in the hall don't show the seed to her either. Natane then goes on to raise the seed on her own, and experiments a bit with it on her own, as in the picture.
The second one actually happens after that though. Natane gets worried about condoms so she goes to Namiki's room to get one. At that point choosing to not go in has Natane continue with Taneo on her own and choosing to go in has Namiki show up and get invited in on the fun. That's where she does what's in the picture (In the other Namiki ending JG00 described she's only shown doing it doggie-style).
