From this rather interesting (slightly spoilery) interview with Sera Gamble:
There's so much Sam coming. There's more Dean coming, there's more Sam coming, and Sam and Dean... are coming together. They're... moving inexorably together. But there is a lot of Sam coming.*
A HA HA HA HA HA HA HA HA HA HA HA
*some words missing
There's so much Sam coming. There's more Dean coming, there's more Sam coming, and Sam and Dean... are coming together. They're... moving inexorably together. But there is a lot of Sam coming.*
A HA HA HA HA HA HA HA HA HA HA HA
*some words missing