face pressed against glass
When you shove your smushed face up against a window like a kid who got kicked out of the candy store and wants to see what's on the other side.
My cousin face pressed against the bus window like he was trying to punch the driver through the glass.
She pressed her face against the classroom window like she was about to scream at the principal.
He face pressed against the prison window like he was planning an escape through his nose.