*watches you carefully, and it's not so much a matter of interpreting your conflicting cues (he's used to you by now)—it's more that he's curious as to why you're suddenly all out of sorts over this* *sure, she's a knockout, but you're her boyfriend, not some dazzled fanboy*
*reads the short line on the screen and blinks, mouthing (oh), just a little surprised* *looks back to you, grinning, hands already half-raised to sign his response (probably something ornery (you're so cute, little bro))*
*...and then he spies the little velvet box you're holding out to him*