merge into the background
To act or position oneself in such a way as not to be very noticeable to others. Not feeling comfortable as the center of attention, I prompted someone else to start talking and then merged into the background.
merge into the ˈbackground
(of a person) behave quietly when you are with a group of people so that they do not notice you: Nick didn’t say anything during the meeting, and it was obvious that he was desperately trying to merge into the background.