Smokestack + Bitterblossom

[Shawon]

My opponent has a Smokestack with two soot counters.
I have a Bitterblossom and 2 Faerie Rogues and etc.

My opponent passes the turn.

During my upkeep, what happens, or what can happen, given my choices?

Can I add a token first, and then sac to Smokestack, or is the other way around? My understanding is that since I am the active player, I can choose the order of the stack.

Thank you in advance.

[Nihil Credo]

If the Smokestack belongs to your opponent and the Bitterblossom to you, here's what happens: at the beginning of your upkeep, both of the abilities trigger.

The active player's (i.e. yours) abilities (i.e. Blossom trigger) are put on the stack first (i.e. they end up on the bottom of the stack).
Then the nonactive player's (i.e. your opponent's) abilities (i.e. Stax trigger) are put on the stack last (i.e. they end up at the top of the stack).

Assuming both players just pass priority, the Stax trigger resolves first and then the Blossom trigger (i.e. you get pwned).