Seth admittedly blushed quite a bit, when Gyre plants the kiss, though mostly from getting flustered, and being surprised by it. He really hadn't expected that...
Though he couldn't say he exactly minded it...
It really had been ages since he'd gotten to enjoy physical touch that hadn't led to harm. Mostly because he had shut himself away from the world but that was due to him becoming scared of the world outside his home.

So Seth...already kind of missed the physical contact.
He could hear Gyre just fine, stumbling to sign back. He had absolutely no idea if there was any kind of real meaning to the kiss.

"O-oh no, it's...it's okay. I was pretty surprised but...I didn't exactly mind that and...I really enjoyed the hug..." Seth admitted though blushed a little bit more at actually admitting that.