It is definitely not that powerful. It's not spring-loaded or anything like that. The design relies on the pulling power of the recipient to make the glitter disperse.

So unless you've got a really buff girlfriend (think: http://www.the-top-list.com/wp-content/uploads/2012/04/ugly_10.jpg) pulling with all her might whilst keeping her eyes wide open, there shouldn't be an issue.

No guarantees though on the reaction of your girlfriend.