you just buy it and when you miss a day it will activate but if you miss two consecutive with out buying a new day streak freeze your streak will be gone

Yes =)

It is like you've banked it, you have it in storage for a rainy day. It will stave off the inevitable for one day. :)

eeyup. that's right.

Hi TwentyOneDragons,

I recommend reading Checked your Streak Freeze Today?. It covers some common pitfalls of keeping a streak and keeping a streak freeze. It'll help you protect your streak better. :)

All About Streak Freezes

1Q. When you buy a streak freeze, does it just sit there until you use it?

1A: After you buy a Streak Freeze, it says "Equipped" and is saved until you need to use it. (I feel you; I was so scared it wouldn't just sit there but hit "Get for: 10 lingots" anyway)

2Q. What if you get it, and then the next day you miss a day? Does it automatically activate and hold your streak??

2A: Yes. It will activate automatically and save your streak.

<BONUS>

3Q. Can I buy it on the day I use it?

3A: I believe so. I did it once. It was equipped, then used.