Obviously valid way to have a shared dream!

Ahh, I was just kidding. Shared dreaming isn't proven yet. However, I do have a way to induce a - fake - shared dream.

First, we have two people, say, Alice and Bob. Alice and Bob discuss in very great detail how the dream world will look like. Then they invent every single DC in the world. Yes, this is not Inception, you CAN design the DCs. Or simply eliminate the DCs. Then they actually write a script for their conversation in the dream and what they do. It should be at least as detailed as one for a movie. Finally, Alice and Bob go to sleep and act out their parts of the script while imagining the other person doing so too. You get a shared dream.

Seriously, that isn't a very good way to do shared dreaming, nor is it a fun way.

Well, I believe you can have a shared dream another way, and have it be real too. Just have two people intend to share dreams, and as they both fall asleep, think about the other person. How their presence feels and an agreed place. Both people have to remember the dream though, and if they do, it's confirmed!

Assuming someone writes out a script exactly, the dream of each person will still be different. Their perceptions will be different--each person's details within the dreamscape will be different. If they decide to meet in a place they both frequently visit, such as a school, house, etc., each person will remember and emphasize different details of the area. Therefore the dream will be different and most likely unfold differently.

Just my thoughts. :P

You have a very creative\imaginative mind! Haha.