6s, how do you prefer to be treated/comforted when overwhelmed by negative emotion? When you make an emotion-related problem aware to another, what kind of response do you hope for? What is the worst thing someone can do when you are in distress?
(Bonus question, if you're interested: how do you go about comforting others when you see them in distress?)
Listen to me talk. Reassure me that my feelings are not abnormal. If I seem like I'm trying to sense-check something ("Am I just being paranoid? Am I? Am I? Why does this stuff always happen to me?"), be realistic if you must but don't say "oh come on, you can't be serious!" or anything like that. (Something along the lines of "oh, I totally understand why you feel that way, I probably would too...but I don't think he meant it to come out like that" and then explain why, would probably help. Or, depending on the situation: "No, I don't think you're paranoid at all and it's completely normal you would feel that way. I would probably be even more upset if I were you!")
Remind me that I'm loved. Tell me you appreciate me, ask me if you can do something for me. Offer to do something concrete. Show that you're loyal and reassuring. If you're someone I value and I seem somehow anxious about the people around me or my relationships, reassure me of the good people in my life and their care for me, including your own.
By the way, I don't usually need the above very badly. I am anxious but mostly it's not that obvious externally (though i think I am getting a little worse as I get older.) But...sometimes I need it more than I'm letting on.
As for how I comfort or reassure others: Similar things, I guess. I will acknowledge and not dismiss their feelings, but also try to bring in gentle reality checks (sometimes you have to be very gentle about this.) Reassure them I'm there for them, tell them how I intend to offer support, tell them it's normal to have such feelings, etc.
Act calm. Surprisingly, I'm very good at that (or perhaps not surprisingly - I think with a lot of 6s the anxiety is not very externally expressed.) A lot of people over the years have told me I'm calm and it has helped them calm down.