this needs to be a episode! Either one where Twilight reminisces with Spike, Cadence, and Shining or they actually go on an adventure where the episode is a guy day and girl day. Which would create two episodes like Just for Sidekicks and Games Ponies Play.
There could be same timeslot episodes here like they did with "Games Ponies Play: and "Just For Sidekicks". One episode could be Twilight and Cadance having a girls day out with maybe the other manes taking part. While in the other being Shining Armor and Spike do a bit of bonding. Maybe Shining could help Spike get tougher so he can actually defend himself.