"I've done that before, actually," Tony said, nodding. "I can show you right where it is. Gus and I went when he was in junior high for a school project."
Apparently Gus had done such a good job of staying out of things that he'd drawn attention to himself. Unwanted attention, this detracting from whatever father-daughter bonding... thing... was going on.
"Hmm?" he said, realizing she was talking to him. "Yeah, I'm fine. I'm just as enthralled by my father's fascinating stories as ever." A hint of sarcasm, but nothing ill meant by it. Gus didn't want to make a scene. If he did, he'd hear about it from his father, but not until Gianna left.