Imagine your younger age gap F/O deliberately dressing and acting younger than they are in order to tease and embarrass you. They do it when you go out together, hanging on your arm and talking in a childish manner while other people are watching.

Or

Imagine deliberately dressing and acting younger than you are in order to tease and embarrass your older age gap F/O. You do it when. They two of you go out together, hanging on their arm and talking in a childish manner while other people are watching.