Just the same way it was cheating during the Firefly group watch. It's fine if you do it, just don't talk about things that aren't happening for everyone yet.

I don't think reading it and discussing it later will work well in this medium, as it hasn't yet.

I know that everyone reads at different paces, which is why I said you can read at whatever pace you want, but shouldn't talk about things that have happened before where everyone is, even if it's spoilered, as that breaks up the flow of conversation.