Most Helpful Guy
A hard question on a macbook?
Well, as I recall Apple borrowed FreeBSD's kernel, and with it, should be the PF (stands for 'Packet Filter') firewall which is a bit complex to configure for your average computer tech, although a seasoned network administrator could nail it.
Tell him you would like to enable PF for your macbook and you want to write a configuration file for it -- no GUI options -- because you want to umm... a highly specific ruleset. That umm, does network address translation (NAT) for another computer behind it on your LAN. Yep, you're throwing your macbook into routing mode.
Then ummm... talk to him. About... well... you're the one who came up with this hair brained scheme :P
Most Helpful Girl
Why don't you want him to think you're interested? Are you interested in him? If you are you should talk to him and be confident. If you want anything to happens betwen you and him it shouldn't matter that you showed him that you're interested first