Rae is just looking at the other man. He has no idea what to do, and for a while it feels like he has just frozen in place. He ends up lifting his hands and grabbing onto Chris' collar, before he just pulls him down to his level and kisses him. He literally has no idea how 'proper' humans socialize with each other. It's something he still hasn't been able to grasp, and he probably never will. At least he is trying to make things pretty clear right now.