Handing a friend your phone is easy. Not scrolling theirs when they hand you theirs is the real trust.

Offering your own phone proves little, since you know what is on it. The harder half is what you do with access you did not have to be given. Looking at one more message after the photo you were shown is a tiny decision that nobody will ever find out about, which is exactly what makes it a measure of you.

Hand it straight back when the thing you were shown is finished. Do not scroll one further, do not read the notification that arrives. That habit is invisible for a long time and then it is the reason people hand you things.