@Shard Your comments were good too, no need for them to be removed!
Hmmm. Eye contact works just fine for me. Now that I think of it, that does seem more sensible.
I do, however, want to keep away from the aura being a purely 'affects people's emotions' thing - in the first RP I tried this powerset with, it was, and it was kind of just a 'your character thinks this about me because I said so', which is never good. As a result, people tended to just sort of ignore it.
The idea of it dialing up with his emotions is a good one, though. I never want it to be totally unnoticeable, but in regular circumstances it could be more 'goosebumps and this guy's weird', which would go with the fact that he tends to show up behind people, say cryptic but comforting things about their personal life, and then just walk away, and when he gets more emotional it might get cranked up to 'vomiting, nosebleeds and oh god what the fuck is this thing'. I think that strikes a good balance - he'll never exactly have a thriving social life, but a few particularly patient people could manage to be his friend.
And the signals thing is totally fine, I just wanted to justify the idea that animals don't like him. If that can get baked into the aura, then that works for me - maybe they're just more sensitive to it?
Thank you for the comments!