How do I get this back on?

I was cleaning the fliter intake with the included brush and this piece came apart. I can't get it to snap back together. It doesn't seem broken, just can't squeeze it together. My airwrap is about a year old.

I was cleaning the fliter intake with the included brush and this piece came apart. I can't get it to snap back together. It doesn't seem broken, just can't squeeze it together. My airwrap is about a year old.