TL;DR Loki is touch starved and has problems with touching (from a person with the same reaction to touch)
Short explanation:
As a person with touching problems (i don't like that much when someone touch me, but I am also touch starved, let's face it xD), who wasn't touched/huged that much as a child and was a little loner in school and some other shit with "hugs are for 'recharging your batteries' or as reward"...
It's a surprise when someone touches you... One of my best friends hug me almost every day for 4 years at school (To say hi to me or give me a surprise hug or something) and my reaction was always the same... 2-3 sec to "Someone I like touched me... WoW"freeze, "I like this? Or maybe not?"thinking and then I hug her back
So yes... Loki's face and all body reaction looks like normal respond from person like me... And it hit much more, when you start thinking about it...
loki’s surprised face when sylvie touches his hand...the way he’s never felt like this before i’m sorry i ship them they hit hard