How Do You React

My eldest son is 4 years old. He's naive, playful, witty, responsible and handsome. He has a way of saying the right things at the right time. Just like yesterday when I was in a sad sad mood, he stared at me and blurted:

Ma, maganda ka talaga.
(Mom, you're really pretty.)
*I smiled.*
Lalo na kapag may earrings ka, mas maganda ka.
(You're much more prettier when you have earrings on.)

So I didn't react so much because I know he's only trying to make me feel good.

The other day though, we were watching XMen and when he saw Rogue, he shouted:

Ano ba yan! Tumatayo ang bird ko! Bakit man ito tumatayo?
(Oh my! My "birdie" is standing! Why is this standing?)

I didn't react but then he repeated his statement so I asked him why he thinks his birdie stands when he sees Rogue. He said:

Ganyan talaga yan, pag makakita ako ng sexy nagatayo talaga yan siya!
(That's just the way it is. When I see sexy women, my birdie really stands!)

I laughed and let him be because he answered his own question perfectly. What do you think I should have done? What do you think should I do?