It is unacceptable to snoop in someone's phone or computer.
Heidi was always curious about what other people did.
Heidi's boyfriend is outside, and she wants to find out what he does on his phone.
Heidi waits until her boyfriend comes in and asks what is on his phone.
Heidi snoops on his phone while her boyfriend is outside.
Heidi's boyfriend shows her everything she is curious about.
Heidi's boyfriend comes in without her noticing and catches her.