When a person become completely enthralled to the point of losing coordination, typically when they are the receiving end of a flatter comment or satisfying action.
I gave her a shoulder massage and she completely melted into my arms.
The effect upon the onlooking cisperson when a trans person goes from passing to being clocked.
Adora: "Hey Eliott I think I just melted that cis back there. All of the pointless rules he created for himself have melted down into a puddle and must now be recast."