What do you think possessive/jealous Q is like?
Pretty protective. Always on the watch for someone who could potentially be hitting on his girlfriend. He would hold her close in public either by simply holding hands or an arm around her waist or shoulders. If he even got a whiff of someone trying to move in on her, he would confront them immediately. It could possibly lead to a shove or even a punch if he felt she was being threatened. He’d spend a lot more time with her. Always checking up on her to see how she’s doing even if it’s by text. If she was going to hangout with friends by herself and a guy friend was with her, he might want to tag along. I don’t think that he would ever be like this in a real relationship, but if I had to guess what he would be like if he was possessive/jealous, this is just how I would imagine he might be.