Seth blinks in surprise, removing one arm to touch his cheek and, oh wow wtf Gyre was right he was crying.
He had not at all expected himself to start crying.

He looks to Gyre sheepishly as he removes his other hand, for the moment, to quickly sign.
"Oh, sorry...I didn't even notice. I'm fine though, nothing's wrong I guess I just...was so happy about you...running your fingers through my hair? I really liked it."

And then he's pretty much diving to wrap his arms around Gyre again, planting his face against him, partially from being a little embarrassed, but mostly from just, not wanting to stop yet.