Here is what I need to know.

Is this so powerful that I have to worry about glitter being shot in my gf eyes?  If not, then I will test it out and video her opening it for you.  I'll tell her its a gift from me and I want to video her reaction.  She wont know its a glitter bomb obv.  As long as she dont attack me and shatter my phone, I can upload the video for you.

No guarantees though on the reaction of your girlfriend.